OSPFv2
OSPF (Open Shortest Path First) is the most popular among the link-state routing protocols. The current IPv4 version, OSPFv2, is widely deployed throughout carrier, ISP, and enterprise networks. OSPFv3 essentially is an IPv6-enabled OSPF. It is a well documented protocol in terms of standards, books, guides, and white paper density.
The knowledge level is high among those who deploy and operate OSPFv2. Integrated IS-IS, however, is catching up in popularity, although those familiar with its addressing already appreciate its simplicity. OSPF is multicast-based (224.0.0.5 = AllSPFRouters, 224.0.0.6 = AllDRouters).
OSPF facilitates 11 different LSA types. This is the biggest obstacle and source for confusion that OSPF apprentices face. OSPF and IS-IS both support Equal-Cost Multi-Path (ECMP), an important feature for optimal link utilization. OSPF uses an arbitrary metric (cost) that is based on link bandwidth in the Cisco implementation.
The Cisco IOS implementation will do equal-cost load balancing for up to six equal-cost routes for OSPF and IS-IS. This condition is characterized by including all routes in the forwarding table. Route tagging and authentication are additional features of modern implementations. Traffic-engineering extensions to OSPF (OSPF-TE) via TE-LSAs are available as well. Traffic engineering in combination with leaf-area concepts is particularly difficult to implement, given the intrinsic behavior of link-state routing protocols.
Lab 9-4: Leaf-Area Design Featuring GateD and Cisco IOS
The topology used in this lab is presented in Figure 9-3. Although this is a rather complex lab, do not get intimidated beforehand.
Three additional Cisco Routers—laurel, hardy and chaplin—are introduced. Each of them has a loopback address configured that is used as the router ID for the OSPF router process configurations as well.
All three UNIX gateways are running GateD. For demonstration of the area concept, four distinct areas have been introduced:
- A backbone area 0
- A regular leaf area 5
- A total stub leaf area 7
- An NSSA leaf area 1 (This area also uses a network range statement for a summary ABR advertisement into the backbone area.)
Examples 9-10 through 9-18 present the Cisco IOS Software and GateD configurations, the kernel routing table, as well as ospf_monitor output and output from the GateD interactive user interface (GII). The ospf_monitor utility requires a start file in the examples named /etc/ospf.mon.
I am aware of the fact that these example listings are somewhat lengthy. Keep in mind that they mostly present status output and serve the purpose that you do not have to rebuild every lab to get the most out of it.
CAUTION
GateD's OSPF operation did not like Linux alias interfaces (eth1:1) in the config file. This appears to be rather a parser (the colon) than an implementation problem. This is the reason why it was removed from Figure 9-3. It will be reintroduced when configuring the same lab with Zebra instances. The use of this notation is deprecated anyway on Linux and will most likely disappear pretty soon.
Example 9-10 shows castor's GateD configuration and accompanying output. The export proto ospfase{} clause is required for route export (redistribution in Cisco terminology). The export of connected interface routes (=direct) and static routes is equivalent to the Cisco IOS experience. The redistribution of kernel routes exports prefixes added via the kernel interface (usually added manually). Remember that these are separate entities on a UNIX gateway.
What are ASE routes exactly? They are autonomous system external routes. This is consistent with Cisco IOS notation. According to Cisco IOS notation, a router that redistributes routes into OSPF is referred to as an autonomous system boundary router (ASBR); the same applies to redistributed routes.
The GateD interactive interface command show ip walkdown 0/0 shows GateD's view of direct, static, connected, kernel, and OSPF routes. The show kernel capabilities are especially important when adding static routes to the gated.cfg file, because not all options (blackhole, reject, hide, and so on) are supported by all operating systems. GateD also communicates this via syslog statements to /var/log/messages.
NOTE
Example 9-10 also presents an overview of OSPF-related timers, which might prove useful to track down adjacency problems. If you have difficulties understanding general OSPF concepts, turn to the "Recommended Reading" section; this book does not offer an in-depth introduction to OSPF or IS-IS.
Example 9-10. Castor GateD Configuration and Output
[root@castor:~#] cat /etc/gated.cfg routerid 192.168.2.7; rip off; ospf yes{ backbone{ networks{ 192.168.2.0 mask 255.255.255.0; 192.168.7.0 mask 255.255.255.0; 192.168.80.0 mask 255.255.255.0; }; interface xl0 ed0 vlan8; }; }; export proto ospfase{ proto static; proto direct; proto kernel; }; [root@castor:~#] netstat -rn -f inet Routing tables Internet: Destination Gateway Flags Refs Use Netif Expire default 192.168.2.254 UGSc 2 15 xl0 127 127.0.0.1 URc 0 0 lo0 127.0.0.1 127.0.0.1 UH 0 38 lo0 192.168.1 192.168.2.254 UGc 1 45 xl0 192.168.1.254 192.168.2.254 UGH 0 34 xl0 192.168.2 link#1 UC 1 0 xl0 192.168.2.254 52:54:05:e3:e4:2f UHLW 9 19 xl0 398 192.168.7 link#2 UC 1 0 ed0 192.168.7.254 00:00:0c:1a:a9:a8 UHLW 5 68 ed0 490 192.168.13/29 192.168.7.254 UGc 0 11 ed0 192.168.14 192.168.2.254 UGc 0 0 xl0 192.168.16/23 192.168.7.254 UGc 0 0 ed0 192.168.19 192.168.2.254 UGc 0 0 xl0 192.168.80 link#14 UC 1 0 vlan8 192.168.80.254 52.54.5.e3.e4.2f UHLW 0 0 vlan8 120 192.168.201.1 192.168.2.254 UGH 0 0 xl0 192.168.201.2 192.168.7.254 UGH 0 0 ed0 192.168.201.3 192.168.7.254 UGH 1 14 ed0 192.168.201.4 192.168.2.254 UGH 0 0 xl0 111.11.117 192.168.2.254 UGc 0 0 xl0 224.0.0.5 127.0.0.1 UH 0 0 lo0 224.0.0.6 127.0.0.1 UH 0 0 lo0 [root@castor:~#] telnet localhost 616 Trying 127.0.0.1... Connected to localhost (127.0.0.1). Escape character is '^]'. Password? 100 Gated Interactive Interface. Version gated-public-3_6 GateD-castor> show interface 100 #ind name address mtu flags 100 #1 xl0 192.168.2.7 1500/1436 Up Broadcast Multicast Simplex Allmulti 100 #2 ed0 192.168.7.7 1500/1436 Up Broadcast Multicast Simplex Allmulti 100 #13 lo0 127.0.0.1 16384/16320 Up Loopback Multicast 100 #14 vlan8 192.168.80.1 1496/1432 Up Broadcast Multicast Simplex GateD-castor> show ip walkdown 0/0 100 Ker 0.0.0.0/0 192.168.2.254 IGP (Id 1) 100 Sta 127/8 127.0.0.1 IGP (Id 1) 100 Dir 127.0.0.1/32 127.0.0.1 IGP (Id 1) 100 OSP 192.168.1/24 192.168.2.254 IGP (Id 1) 100 Ker 192.168.1.2/32 192.168.2.254 IGP (Id 1) 100 OSP 192.168.1.254/32 192.168.2.254 IGP (Id 1) 100 Dir 192.168.2/24 192.168.2.7 IGP (Id 1) 100 Dir 192.168.7/24 192.168.7.7 IGP (Id 1) 100 OSP 192.168.13/29 192.168.7.254 IGP (Id 1) 100 OSP 192.168.14/24 192.168.2.254 IGP (Id 1) 100 OSP 192.168.16/23 192.168.7.254 IGP (Id 1) 100 OSP 192.168.19/24 192.168.2.254 IGP (Id 1) 100 Dir 192.168.80/24 192.168.80.1 IGP (Id 1) 100 OSP 192.168.201.1/32 192.168.2.254 IGP (Id 1) 100 OSP 192.168.201.2/32 192.168.7.254 IGP (Id 1) 100 OSP 192.168.201.3/32 192.168.7.254 IGP (Id 1) 100 OSP 192.168.201.4/32 192.168.2.254 IGP (Id 1) 100 OSP 111.11.117/24 192.168.2.254 IGP (Id 1) GateD-castor> show ip route 192.168.16.0/23 100 Route 192.168.16 - 255.255.254 entries 1 Announced 1 Depth 0 <> 100 Proto Next Hop Source Gwt Preference/2 Metric/2 etc... 100 * OSPF 192.168.7.254 --- 10/0 7/-1 0 22:16:49 IGP(Id 1)
GateD-castor> show timer 100 Name Task Last Next Intrvl Jitter flags 100 AGE IF 00:00s 00:05s 00:00s 00:00s 100 Retransmit OSPF 00:04s 00:01s 00:05s 00:00s <> 100 Adjacency OSPF 00:00s 00:15s 00:00s 00:00s 100 Hello OSPF 00:09s 00:01s 00:10s 00:00s 100 Retransmit OSPF 00:00s 00:05s 00:05s 00:00s <> 100 Adjacency OSPF 00:00s 00:09s 00:00s 00:00s 100 Hello OSPF 00:00s 00:10s 00:10s 00:00s 100 Retransmit OSPF 00:01s 00:04s 00:05s 00:00s <> 100 Adjacency OSPF 00:00s 00:14s 00:00s 00:00s 100 Hello OSPF 00:01s 00:09s 00:10s 00:00s 100 Lock OSPF 00:01s 00:04s 00:05s 00:00s <> 100 Ack OSPF 00:06s 00:00s 00:00s 00:00s 100 LSDBAseAge OSPF 00:24s 00:37s 01:01s 00:00s <> 100 LSDBSumAge OSPF 02:44s 12:16s 15:00s 00:00s <> 100 LSDBIntAge OSPF 03:48s 11:12s 15:00s 00:00s <> 100 LSAGenInt OSPF 22:34s 07:26s 30:00s 00:00s <> 100 LSAGenAse OSPF 00:05s 00:02s 00:07s 00:00s <> 100 AseQueue OSPF 19:33s 00:00s 00:00s 00:00s 100 IfCheck KRT 00:11s 00:49s 01:00s 00:00s <> 100 Timeout KRT 00:00s 00:00s 00:00s 00:00s 100 Age Redirect 00:00s 00:49s 00:00s 00:00s 100 Startup SMUX 00:11s 00:49s 01:00s 00:00s <> GateD-castor> show kernel 100 Kernel options: <> Support: 100 IP forwarding: 1 UDP checksums 1 100 The time is 22:18:47
Example 9-11 introduces the powerful ospf_monitor utility with its accompanying configuration file and the resulting monitoring output. It is part of the GateD binaries. The configuration file just includes remote hosts, which should be monitored. The especially helpful thing about ospf_monitor is that it offers a rich set of queries for local and remote hosts running GateD. At the beginning of Example 9-11, the ospf_monitor help facility explains the abbreviated queries used.
Example 9-11. Callisto ospf_monitor Output for Remote Host Castor
[root@callisto:~#] cat /etc/ospf.mon 192.168.1.254 ganymed 192.168.1.1 callisto 192.168.2.7 castor 192.168.1.2 pollux [root@callisto:~#] ospf_monitor /etc/ospf.mon [ 1 ] dest command params > ? Local commands: ?: help ?R: remote command information d: show configured destinations h: show history x: exit @: use last destination @ : use configured destination F : write monitor information to filename S: write monitor information to stdout (default) [ 2 ] dest command params > ?R Remote-commands: a : show link state advertisement c: show cumulative log e: show cumulative errors l: dump lsdb (except for ASEs) A: dump ASEs W: dump ASEs with LSIDs o: print ospf routing table I: show interfaces h: show next hops N : show neighbors - if r is set will print retrans lst [ 3 ] dest command params > d 1: 192.168.1.254 ganymed 2: 192.168.1.1 callisto 3: 192.168.2.7 castor 4: 192.168.1.2 pollux [ 4 ] dest command params > @3 N remote-command sent to 192.168.2.7 Source <<192.168.2.7 castor>> Interface: 192.168.2.7 Area: 0.0.0.0 Router Id Nbr IP Addr State Mode Prio ------------------------------------------------------ 192.168.44.1 192.168.2.254 Full Slave 1 Interface: 192.168.7.7 Area: 0.0.0.0 Router Id Nbr IP Addr State Mode Prio ------------------------------------------------------ 192.168.201.2 192.168.7.254 Full Slave 1 Interface: 192.168.80.1 Area: 0.0.0.0 Router Id Nbr IP Addr State Mode Prio ------------------------------------------------------ 192.168.44.1 192.168.80.254 Full Slave 1 done [ 5 ] dest command params > @3 I remote-command sent to 192.168.2.7 Source <<192.168.2.7 castor>> Area: 0.0.0.0 IP Address Type State Cost Pri DR BDR ---------------------------------------------------------------------- 192.168.2.7 Bcast DR Other 1 0 192.168.2.254 None 192.168.7.7 Bcast DR Other 1 0 192.168.7.254 None 192.168.80.1 Bcast DR Other 1 0 192.168.80.254 None done [ 7 ] dest command params > @3 h remote-command sent to 192.168.2.7 Source <<192.168.2.7 castor>> Next hops: Address Type Refcount Interface ------------------------------------------------------------- 192.168.2.7 Direct 3 192.168.2.7 xl0 192.168.2.254 Neighbor 30 192.168.2.7 xl0 192.168.7.7 Direct 3 192.168.7.7 ed0 192.168.7.254 Neighbor 16 192.168.7.7 ed0 192.168.80.1 Direct 3 192.168.80.1 vlan8 192.168.80.254 Neighbor 1 192.168.80.1 vlan8 done [ 8 ] dest command params > @3 o remote-command sent to 192.168.2.7 Source <<192.168.2.7 castor>> AS Border Routes: Router Cost AdvRouter NextHop(s) ---------------------------------------------------- Area 0.0.0.0: 192.168.2.7 0 192.168.2.7 192.168.201.2 1 192.168.201.2 192.168.7.254 192.168.44.1 1 192.168.44.1 192.168.2.254 192.168.1.1 2 192.168.1.1 192.168.2.254 Total AS Border routes: 4 Area Border Routes: Router Cost AdvRouter NextHop(s) ---------------------------------------------------- Area 0.0.0.0: 192.168.201.4 13 192.168.201.4 192.168.2.254 192.168.201.2 1 192.168.201.2 192.168.7.254 192.168.1.1 2 192.168.1.1 192.168.2.254 Total Area Border Routes: 3 Summary AS Border Routes: Router Cost AdvRouter NextHop(s) --------------------------------------------------- 192.168.201.1 3 192.168.1.1 192.168.2.254 Total Summary AS Border Routes: 1 Networks: Destination Area Cost Type NextHop AdvRouter ---------------------------------------------------------------------------- 192.168.7 0.0.0.0 1 Net 192.168.7.7 192.168.201.2 192.168.201.2 0.0.0.0 2 Stub 192.168.7.254 192.168.201.2 192.168.16/23 0.0.0.0 7 SNet 192.168.7.254 192.168.201.2 192.168.13.0/29 0.0.0.0 7 SNet 192.168.7.254 192.168.201.2 192.168.201.3 0.0.0.0 8 SNet 192.168.7.254 192.168.201.2 192.168.2 0.0.0.0 1 Net 192.168.2.7 192.168.44.1 192.168.80 0.0.0.0 1 Net 192.168.80.1 192.168.44.1 192.168.1 0.0.0.0 2 Net 192.168.2.254 192.168.44.1 192.168.19 0.0.0.0 13 SNet 192.168.2.254 192.168.1.1 192.168.14 0.0.0.0 3 SNet 192.168.2.254 192.168.1.1 192.168.201.1 0.0.0.0 4 SNet 192.168.2.254 192.168.1.1 192.168.201.4 0.0.0.0 14 SNet 192.168.2.254 192.168.201.4 ASEs: Destination Cost E Tag NextHop AdvRouter ----------------------------------------------------------------------------- 0.0.0.0 1 1 c0000000 192.168.2.254 192.168.44.1 111.11.117 1 1 c0000000 192.168.2.254 192.168.44.1 192.168.1.254 1 1 c0000000 192.168.2.254 192.168.44.1 Total nets: 12 Intra Area: 4 Inter Area: 8 ASE: 3 done [ 10 ] dest command params > @3 e remote-command sent to 192.168.2.7 Source <<192.168.2.7 castor>> Packets Received: 5: Monitor request 549: Hello 13: DB Description 0: Link-State Req 86: Link-State Update 20: Link-State Ack Packets Sent: 0: Monitor response 551: Hello 14: DB Description 3: Link-State Req 96: Link-State Update 28: Link-State Ack Errors: 0: IP: bad destination 0: IP: bad protocol 0: IP: received my own packet 0: OSPF: bad packet type 0: OSPF: bad version 0: OSPF: bad checksum 0: OSPF: bad area id 0: OSPF: area mismatch 0: OSPF: bad virtual link 0: OSPF: bad authentication type 0: OSPF: bad authentication key 0: OSPF: packet too small 0: OSPF: packet size > ip length 0: OSPF: transmit error 0: OSPF: interface down 0: OSPF: unknown neighbor 0: HELLO: netmask mismatch 0: HELLO: hello timer mismatch 0: HELLO: dead timer mismatch 0: HELLO: extern option mismatch 0: HELLO: router id confusion 0: HELLO: virtual neighbor unknown 0: HELLO: NBMA neighbor unknown 0: DD: neighbor state low 0: DD: router id confusion 0: DD: extern option mismatch 0: DD: unknown LSA type 0: LS ACK: neighbor state low 0: LS ACK: bad ack 0: LS ACK: duplicate ack 0: LS ACK: Unknown LSA type 0: LS REQ: neighbor state low 0: LS REQ: empty request 0: LS REQ: bad request 0: LS UPD: neighbor state low 0: LS UPD: newer self-gen LSA 0: LS UPD: LSA checksum bad 3: LS UPD: received less recent LSA 0: LS UPD: unknown LSA type done [ 11 ] dest command params > @3 c remote-command sent to 192.168.2.7 Source <<192.168.2.7 castor>> IO stats Input Output Type 6 0 Monitor request 561 566 Hello 13 14 DB Description 0 3 Link-State Req 88 100 Link-State Update 21 28 Link-State Ack ASE: 7 checksum sum 387C5 LSAs originated: 10 received: 73 Router: 5 ASE: 5 Area 0.0.0.0: Neighbors: 3 Interfaces: 3 Spf: 11 Checksum sum EE7DB DB: rtr: 5 net: 4 sumasb: 6 sumnet: 13 Routing Table: Intra Area: 4 Inter Area: 8 ASE: 3 done
Examples 9-12 and 9-13 show the configuration of two virtual links to connect the isolated total stub area 7 to the backbone area via a transit area 5. Virtual links always connect two ABRs; in our example, the two virtual links connect scar/callisto and chaplin. GateD uses different default timer settings than Cisco IOS Software; this explains the additional configuration lines in the callisto gated.conf file to bring the tunnels up. Callisto and scar act as ABRs.
Example 9-12. Callisto GateD Configuration and Output
[root@callisto:~#] cat /etc/gated.conf routerid 192.168.1.1; rip off; ospf yes{ backbone{ networks{ 192.168.1.0 mask 255.255.255.0; }; interface eth1; virtuallink neighborid 192.168.201.4 transitarea 5 { hellointerval 10; routerdeadinterval 40; retransmitinterval 5; transitdelay 40; }; }; area 5{ networks{ 192.168.14.0 mask 255.255.255.0; }; interface eth0; }; }; static{ default gateway 192.168.1.254; }; export proto ospfase{ proto static{all; }; proto direct{all; }; proto kernel{all; }; }; [root@callisto:~#] ip route 192.168.201.2 via 192.168.1.254 dev eth1 proto gated 192.168.201.3 via 192.168.1.254 dev eth1 proto gated 192.168.201.1 via 192.168.14.2 dev eth0 proto gated 192.168.1.2 via 192.168.1.254 dev eth1 proto gated 224.0.0.6 via 127.0.0.1 dev lo proto gated scope link 192.168.201.4 via 192.168.14.2 dev eth0 proto gated 224.0.0.5 via 127.0.0.1 dev lo proto gated scope link 192.168.1.254 via 192.168.1.254 dev eth1 proto gated 127.0.0.1 dev lo proto gated scope link 192.168.13.0/29 via 192.168.1.254 dev eth1 proto gated 192.168.7.0/24 via 192.168.1.254 dev eth1 proto gated 111.11.117.0/24 via 192.168.1.254 dev eth1 proto gated 192.168.19.0/24 via 192.168.14.2 dev eth0 proto gated 192.168.2.0/24 via 192.168.1.254 dev eth1 proto gated 192.168.80.0/24 via 192.168.1.254 dev eth1 proto gated 192.168.1.0/24 dev eth1 proto gated scope link 192.168.14.0/24 dev eth0 scope link 192.168.16.0/23 via 192.168.1.254 dev eth1 proto gated unreachable 127.0.0.0/8 proto gated scope link default via 192.168.1.254 dev eth1 [root@callisto:~#] netstat -rne Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 192.168.201.2 192.168.1.254 255.255.255.255 UGH 0 0 0 eth1 192.168.201.3 192.168.1.254 255.255.255.255 UGH 0 0 0 eth1 192.168.201.1 192.168.14.2 255.255.255.255 UGH 0 0 0 eth0 192.168.1.2 192.168.1.254 255.255.255.255 UGH 0 0 0 eth1 224.0.0.6 127.0.0.1 255.255.255.255 UGH 0 0 0 lo 192.168.201.4 192.168.14.2 255.255.255.255 UGH 0 0 0 eth0 224.0.0.5 127.0.0.1 255.255.255.255 UGH 0 0 0 lo 192.168.1.254 192.168.1.254 255.255.255.255 UGH 0 0 0 eth1 127.0.0.1 0.0.0.0 255.255.255.255 UH 0 0 0 lo 192.168.13.0 192.168.1.254 255.255.255.248 UG 0 0 0 eth1 192.168.7.0 192.168.1.254 255.255.255.0 UG 0 0 0 eth1 111.11.117.0 192.168.1.254 255.255.255.0 UG 0 0 0 eth1 192.168.19.0 192.168.14.2 255.255.255.0 UG 0 0 0 eth0 192.168.2.0 192.168.1.254 255.255.255.0 UG 0 0 0 eth1 192.168.80.0 192.168.1.254 255.255.255.0 UG 0 0 0 eth1 192.168.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1 192.168.14.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0 192.168.16.0 192.168.1.254 255.255.254.0 UG 0 0 0 eth1 127.0.0.0 - 255.0.0.0 ! 0 - 0 - 0.0.0.0 192.168.1.254 0.0.0.0 UG 0 0 0 eth1 [root@callisto:~#] ospf_monitor /etc/ospf.mon listening on 0.0.0.0.33862 [ 1 ] dest command params > @2 N remote-commandsent to 192.168.1.1 Source <<192.168.1.1 callisto>> Interface: 192.168.1.1 Area: 0.0.0.0 Router Id Nbr IP Addr State Mode Prio ------------------------------------------------------ 192.168.44.1 192.168.1.254 Full Slave 1 Interface: 192.168.14.1 Area: 0.0.0.5 Router Id Nbr IP Addr State Mode Prio ------------------------------------------------------ 192.168.201.1 192.168.14.2 Full Slave 1 192.168.201.2 192.168.14.254 Full Slave 1 Virtual links: Interface Router Id Nbr IP Addr State Mode Prio ---------------------------------------------------------------------- 192.168.14.1 192.168.201.4 192.168.19.2 Full Slave 0 done [ 5 ] dest command params > @2 I remote-command sent to 192.168.1.1 Source <<192.168.1.1 callisto>> Area: 0.0.0.0 IP Address Type State Cost Pri DR BDR ---------------------------------------------------------------------- 192.168.1.1 Bcast DR Other 1 0 192.168.1.254 None Area: 0.0.0.5 IP Address Type State Cost Pri DR BDR ---------------------------------------------------------------------- 192.168.14.1 Bcast DR Other 1 0 192.168.14.254 192.168.14.2 Virtual Links: Transit Area Router ID Remote IP Local IP Type State Cost ----------------------------------------------------------------------------------- 0.0.0.5 192.168.201.4 192.168.19.2 192.168.14.1 Virt P To P 11 done [ 7 ] dest command params > @2 h remote-command sent to 192.168.1.1 Source <<192.168.1.1 callisto>> Next hops: Address Type Refcount Interface ------------------------------------------------------------- 192.168.1.1 Direct 3 192.168.1.1 eth1 192.168.1.254 Neighbor 33 192.168.1.1 eth1 192.168.14.1 Direct 3 192.168.14.1 eth0 192.168.14.2 Neighbor 15 192.168.14.1 eth0 192.168.14.254 Neighbor 4 192.168.14.1 eth0 192.168.19.2 Neighbor 1 192.168.14.1 eth0 done [ 10 ] dest command params > @2 c remote-command sent to 192.168.1.1 Source <<192.168.1.1 callisto>> IO stats Input Output Type 13 0 Monitor request 8720 8225 Hello 75 129 DB Description 27 34 Link-State Req 568 479 Link-State Update 221 315 Link-State Ack ASE: 7 checksum sum 381C8 LSAs originated: 159 received: 359 Router: 20 SumNet: 104 SumASB: 29 ASE: 6 Area 0.0.0.0: Neighbors: 2 Interfaces: 1 Spf: 28 Checksum sum 10C3EC DB: rtr: 5 net: 4 sumasb: 6 sumnet: 13 Area 0.0.0.5: Neighbors: 2 Interfaces: 1 Spf: 18 Checksum sum 14C6DE DB: rtr: 4 net: 2 sumasb: 9 sumnet: 27 Routing Table: Intra Area: 6 Inter Area: 6 ASE: 5 Done [ 12 ] dest command params > @2 o remote-command sent to 192.168.1.1 Source <<192.168.1.1 callisto>> AS Border Routes: Router Cost AdvRouter NextHop(s) ---------------------------------------------------- Area 0.0.0.0: 192.168.2.7 2 192.168.2.7 192.168.1.254 192.168.201.2 3 192.168.201.2 192.168.1.254 192.168.44.1 1 192.168.44.1 192.168.1.254 192.168.1.1 0 192.168.1.1 Area 0.0.0.5: 192.168.201.2 1 192.168.201.2 192.168.14.254 192.168.201.1 1 192.168.201.1 192.168.14.2 192.168.1.1 0 192.168.1.1 Total AS Border routes: 7 Area Border Routes: Router Cost AdvRouter NextHop(s) ---------------------------------------------------- Area 0.0.0.0: 192.168.201.4 11 192.168.201.4 192.168.14.2 192.168.201.2 3 192.168.201.2 192.168.1.254 192.168.1.1 0 192.168.1.1 Area 0.0.0.5: 192.168.201.4 11 192.168.201.4 192.168.14.2 192.168.201.2 1 192.168.201.2 192.168.14.254 192.168.1.1 0 192.168.1.1 Total Area Border Routes: 6 Summary AS Border Routes: Router Cost AdvRouter NextHop(s) --------------------------------------------------- Networks: Destination Area Cost Type NextHop AdvRouter ---------------------------------------------------------------------------- 192.168.1 0.0.0.0 1 Net 192.168.1.1 192.168.44.1 192.168.14 0.0.0.5 1 Net 192.168.14.1 192.168.201.2 192.168.19 0.0.0.5 11 Net 192.168.14.2 192.168.201.4 192.168.201.1 0.0.0.5 2 Stub 192.168.14.2 192.168.201.1 192.168.2 0.0.0.0 2 Net 192.168.1.254 192.168.44.1 192.168.80 0.0.0.0 2 Net 192.168.1.254 192.168.44.1 192.168.201.2 0.0.0.0 4 Stub 192.168.1.254 192.168.201.2 192.168.16/23 0.0.0.0 9 SNet 192.168.1.254 192.168.201.2 192.168.7 0.0.0.0 3 Net 192.168.1.254 192.168.201.2 192.168.201.3 0.0.0.0 10 SNet 192.168.1.254 192.168.201.2 192.168.13.0/29 0.0.0.0 9 SNet 192.168.1.254 192.168.201.2 192.168.201.4 0.0.0.0 12 SNet 192.168.14.2 192.168.201.4 ASEs: Destination Cost E Tag NextHop AdvRouter ----------------------------------------------------------------------------- 0.0.0.0 1 1 c0000000 192.168.1.254 192.168.44.1 111.11.117 1 1 c0000000 192.168.1.254 192.168.44.1 192.168.1.254 1 1 c0000000 192.168.1.254 192.168.44.1 192.168.1.2 2 1 c0000000 192.168.1.254 192.168.2.7 192.168.1.1 2 1 c0000000 192.168.1.254 192.168.2.7 Total nets: 12 Intra Area: 6 Inter Area: 6 ASE: 5 done
Example 9-13. Callisto GateD Diagnostic Output
[root@callisto:~#] telnet localhost 616 Trying 127.0.0.1... Connected to localhost (127.0.0.1). Escape character is '^]'. Password? 100 Gated Interactive Interface. Version gated-public-3_6 GateD-callisto> show kernel 100 Kernel options: <> Support:100 IP forwarding: 1 UDP checksums 1 100 The time is 22:43:18 GateD-callisto> show timer 100 Name Task Last Next Intrvl Jitter Flags 100 AGE IF 00:00s 02:30s 00:00s 00:00s 100 Retransmit OSPF 00:00s 00:05s 00:05s 00:00s <> 100 Adjacency OSPF 00:00s 00:00s 00:00s 00:00s 100 Hello OSPF 00:05s 00:05s 00:10s 00:00s 100 Retransmit OSPF 00:01s 00:04s 00:05s 00:00s <> 100 Adjacency OSPF 00:00s 00:15s 00:00s 00:00s 100 Hello OSPF 00:06s 00:04s 00:10s 00:00s 100 Retransmit OSPF 00:01s 00:04s 00:05s 00:00s <> 100 Adjacency OSPF 00:00s 00:22s 00:00s 00:00s 100 Hello OSPF 00:06s 00:04s 00:10s 00:00s 100 Lock OSPF 00:00s 00:05s 00:05s 00:00s <> 100 Lock OSPF 00:01s 00:04s 00:05s 00:00s <> 100 Ack OSPF 06:14s 00:00s 00:00s 00:00s 100 LSDBAseAge OSPF 00:56s 00:05s 01:01s 00:00s <> 100 LSDBSumAge OSPF 02:59s 12:01s 15:00s 00:00s <> 100 LSDBIntAge OSPF 04:03s 10:57s 15:00s 00:00s <> 100 LSAGenSum OSPF 06:15s 23:45s 30:00s 00:00s <> 100 LSAGenInt OSPF 07:49s 22:11s 30:00s 00:00s <> 100 LSAGenAse OSPF 00:06s 00:01s 00:07s 00:00s <> 100 AseQueue OSPF 128:25s 00:00s 00:00s 00:00s 100 IfCheck KRT 00:02s 00:13s 00:15s 00:00s <> 100 Timeout KRT 00:00s 00:00s 00:00s 00:00s 100 Age Redirect 00:00s 02:58s 00:00s 00:00s 100 Startup SMUX 00:26s 00:34s 01:00s 00:00s <> GateD-callisto> show interface 100 #ind Name Address Mtu Flags 100 #1 lo 127.0.0.1 16436/16372 Up Loopback 100 #2 eth0 192.168.14.1 1500/1436 Up Broadcast Multicast 100 #3 eth1 192.168.1.1 1500/1436 Up Broadcast Multicast 100 #3 eth1 192.168.45.253 1500/1436 Up Broadcast Multicast GateD-callisto> show ip walkdown 0/0 100 Sta 0.0.0.0/0 192.168.1.254 IGP (Id 1) 100 Sta 127/8 127.0.0.1 IGP (Id 1) 100 Dir 127.0.0.1/32 127.0.0.1 IGP (Id 1) 100 Dir 192.168.1/24 192.168.1.1 IGP (Id 1) 100 --- 192.168.1.1/32 --- 100 OSP 192.168.1.2/32 192.168.1.254 IGP (Id 1) 100 OSP 192.168.1.254/32 192.168.1.254 IGP (Id 1) 100 OSP 192.168.2/24 192.168.1.254 IGP (Id 1) 100 OSP 192.168.7/24 192.168.1.254 IGP (Id 1) 100 OSP 192.168.13/29 192.168.1.254 IGP (Id 1) 100 Dir 192.168.14/24 192.168.14.1 IGP (Id 1) 100 OSP 192.168.16/23 192.168.1.254 IGP (Id 1) 100 OSP 192.168.19/24 192.168.14.2 IGP (Id 1) 100 OSP 192.168.80/24 192.168.1.254 IGP (Id 1) 100 OSP 192.168.201.1/32 192.168.14.2 IGP (Id 1) 100 OSP 192.168.201.2/32 192.168.1.254 IGP (Id 1) 100 OSP 192.168.201.3/32 192.168.1.254 IGP (Id 1) 100 OSP 192.168.201.4/32 192.168.14.2 IGP (Id 1) 100 OSP 111.11.117/24 192.168.1.254 IGP (Id 1)
NOTE
Example 9-14 presents the GateD configuration and output of the backbone area gateway ganymed with an example for priority statements to influence DR/BDR election.
Example 9-14. Ganymed GateD Configuration and Routing Table
[root@ganymed:~#] cat /etc/gated.cfg routerid 192.168.44.1; rip off; ospf yes{ backbone{ networks{ 192.168.1.0 mask 255.255.255.0; 192.168.2.0 mask 255.255.255.0; 192.168.80.0 mask 255.255.255.0; }; interface ne3{ priority 1; }; interface ne4{ priority 1; }; interface vlan0{ priority 1; }; }; }; export proto ospfase{ proto static{all; }; proto direct{all; }; proto kernel{all; }; }; [root@ganymed:~#] netstat -rn -f inet Routing tables Internet: Destination Gateway Flags Refs Use Mtu Interface default 111.11.117.1 UGS 3 26477 1500 ne5 127/8 127.0.0.1 UR 0 0 33224 lo0 127.0.0.1 127.0.0.1 UH 1 2 33224 lo0 192.168.1/24 link#1 UC -1850 0 1500 ne3 192.168.1.1 52:54:5:e3:51:87 UHL 4 19241 1500 ne3 192.168.1.2 8:0:46:64:74:1b UHL 1 16446 1500 ne3 192.168.1.254 127.0.0.1 UGHS 0 0 33224 lo0 192.168.2/24 link#2 UC 0 0 1500 ne4 192.168.2.7 0:10:5a:c4:2c:4 UHL 5 4101 1500 ne4 192.168.7/24 192.168.2.7 UG 0 68 1496 ne4 192.168.13.0/29 192.168.2.7 UG 0 11 1500 ne4 192.168.14/24 192.168.1.1 UG -2 2 1500 ne3 192.168.16/23 192.168.2.7 UG 0 0 1496 ne4 192.168.19/24 192.168.1.1 UG 0 0 1500 ne3 192.168.44.1 192.168.44.1 UH 0 0 33224 lo1 192.168.80/24 link#16 UC 0 0 1496 vlan0 192.168.201.1 192.168.1.1 UGH 0 0 1500 ne3 192.168.201.2 192.168.2.7 UGH 0 0 1496 ne4 192.168.201.3 192.168.2.7 UGH 1 53 1500 ne4 192.168.201.4 192.168.1.1 UGH 0 0 1500 ne3 111.11.117/24 link#3 UC 0 0 1500 ne5 111.11.117.1 0:5:9a:5b:23:fc UHL 1 0 1500 ne5 224.0.0.5 127.0.0.1 UH 1 3082 33224 lo0 224.0.0.6 127.0.0.1 UH 0 0 33224 lo0
Example 9-15 shows the ABR router configuration of scar featuring a summary-address statement for testing purposes. The area 1 range 192.168.16.0 255.255.254.0 statement in Example 9-15 enables the ABR scar to consolidate contiguous address ranges into one summary advertisement (at bit-boundaries only, of course). Do not confuse it with the summary-address statement, which has a similar effect when redistribution of foreign protocols into OSPF comes into play.
Example 9-15. Scar Configuration and Diagnostic Output
scar# show running-config ... router ospf 1 router-id 192.168.201.2 log-adjacency-changes area 1 nssa default-information-originate area 1 range 192.168.16.0 255.255.254.0 area 5 virtual-link 192.168.201.4 summary-address 172.16.0.0 255.240.0.0 redistribute connected subnets redistribute static subnets passive-interface Serial0 passive-interface Serial1 passive-interface Serial2 passive-interface Serial3 network 192.168.7.0 0.0.0.255 area 0 network 192.168.13.0 0.0.0.7 area 1 network 192.168.14.0 0.0.0.255 area 5 network 192.168.17.0 0.0.0.7 area 1 network 192.168.201.2 0.0.0.0 area 0 maximum-paths 2 ... ip route 0.0.0.0 0.0.0.0 192.168.7.7 ip route 0.0.0.0 0.0.0.0 192.168.14.1 200 ... scar# sh ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 192.168.2.7 0 FULL/DROTHER 00:00:33 192.168.7.7 Ethernet0 192.168.201.1 1 FULL/BDR 00:00:38 192.168.14.2 Ethernet1 192.168.1.1 0 FULL/DROTHER 00:00:30 192.168.14.1 Ethernet1 192.168.201.3 1 FULL/DR 00:00:30 192.168.13.2 TokenRing0 scar# sh ip ospf border-routers OSPF Process 1 internal Routing Table Codes: i - Intra-area route, I - Inter-area route i 192.168.44.1 [11] via 192.168.7.7, Ethernet0, ASBR, Area 0, SPF 40 i 192.168.1.1 [12] via 192.168.7.7, Ethernet0, ABR/ASBR, Area 0, SPF 40 i 192.168.1.1 [10] via 192.168.14.1, Ethernet1, ABR/ASBR, Area 5, SPF 24 i 192.168.201.3 [6] via 192.168.13.2, TokenRing0, ASBR, Area 1, SPF 11 i 192.168.201.1 [10] via 192.168.14.2, Ethernet1, ASBR, Area 5, SPF 24 i 192.168.201.4 [20] via 192.168.14.2, Ethernet1, ABR, Area 0, SPF 40 i 192.168.201.4 [20] via 192.168.14.2, Ethernet1, ABR, Area 5, SPF 24 i 192.168.2.7 [10] via 192.168.7.7, Ethernet0, ASBR, Area 0, SPF 40 scar# sh ip ospf virtual-links Virtual Link OSPF_VL0 to router 192.168.201.4 is up Run as demand circuit DoNotAge LSA not allowed (Number of DCbitless LSA is 10). Transit area 5, via interface Ethernet1, Cost of using 20 Transmit Delay is 1 sec, State POINT_TO_POINT, Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:00 Adjacency State FULL (Hello suppressed) Index 2/4, retransmission queue length 0, number of retransmission 2 First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0) Last retransmission scan length is 2, maximum is 2 Last retransmission scan time is 0 msec, maximum is 0 msec scar# sh ip ospf summary-address OSPF Process 1, Summary-address 172.16.0.0/255.240.0.0 Metric 16777215, Type 0, Tag 0 scar# sh ip route Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area * - candidate default, U - per-user static route, o - ODR P - periodic downloaded static route Gateway of last resort is 192.168.7.7 to network 0.0.0.0 192.168.13.0/29 is subnetted, 1 subnets C 192.168.13.0 is directly connected, TokenRing0 C 192.168.14.0/24 is directly connected, Ethernet1 192.168.201.0/32 is subnetted, 4 subnets O 192.168.201.1 [110/11] via 192.168.14.2, 00:56:24, Ethernet1 O 192.168.201.3 [110/7] via 192.168.13.2, 01:01:52, TokenRing0 C 192.168.201.2 is directly connected, Loopback0 O IA 192.168.201.4 [110/21] via 192.168.14.2, 00:56:24, Ethernet1 O 192.168.80.0/24 [110/11] via 192.168.7.7, 00:56:24, Ethernet0 O E2 111.11.117.0/24 [110/1] via 192.168.7.7, 00:56:14, Ethernet0 C 192.168.7.0/24 is directly connected, Ethernet0 192.168.17.0/29 is subnetted, 1 subnets C 192.168.17.0 is directly connected, TokenRing1 192.168.1.0/24 is variably subnetted, 4 subnets, 2 masks O E2 192.168.1.1/32 [110/1] via 192.168.7.7, 00:40:20, Ethernet0 O 192.168.1.0/24 [110/12] via 192.168.7.7, 00:56:24, Ethernet0 O E2 192.168.1.2/32 [110/1] via 192.168.7.7, 00:56:14, Ethernet0 O E2 192.168.1.254/32 [110/1] via 192.168.7.7, 00:56:14, Ethernet0 O 192.168.2.0/24 [110/11] via 192.168.7.7, 00:56:24, Ethernet0 O 192.168.19.0/24 [110/20] via 192.168.14.2, 00:56:24, Ethernet1 S* 0.0.0.0/0 [1/0] via 192.168.7.7 O 192.168.16.0/23 is a summary, 01:01:52, Null0 scar# sh ip ospf Routing Process "ospf 1" with ID 192.168.201.2 Supports only single TOS(TOS0) routes Supports opaque LSA It is an area border and autonomous system boundary router Redistributing External Routes from, connected, includes subnets in redistribution static, includes subnets in redistribution SPF schedule delay 5 secs, Hold time between two SPFs 10 secs Minimum LSA interval 5 secs. Minimum LSA arrival 1 secs Number of external LSA 7. Checksum Sum 0x375CE Number of opaque AS LSA 0. Checksum Sum 0x0 Number of DCbitless external and opaque AS LSA 7 Number of DoNotAge external and opaque AS LSA 0 Number of areas in this router is 3. 2 normal 0 stub 1 nssa External flood list length 0 Area BACKBONE(0) Number of interfaces in this area is 3 Area has no authentication SPF algorithm executed 40 times Area ranges are Number of LSA 28. Checksum Sum 0x109802 Number of opaque link LSA 0. Checksum Sum 0x0 Number of DCbitless LSA 10 Number of indication LSA 0 Number of DoNotAge LSA 0 Flood list length 0 Area 1 Number of interfaces in this area is 2 It is a NSSA area Perform type-7/type-5 LSA translation generates NSSA default route with cost 1 Area has no authentication SPF algorithm executed 11 times Area ranges are 192.168.16.0/23 Active(6) Advertise Number of LSA 13. Checksum Sum 0x72D48 Number of opaque link LSA 0. Checksum Sum 0x0 Number of DCbitless LSA 0 Number of indication LSA 0 Number of DoNotAge LSA 0 Flood list length 0 Area 5 Number of interfaces in this area is 1 Area has no authentication SPF algorithm executed 24 times Area ranges are Number of LSA 42. Checksum Sum 0x149EF2 Number of opaque link LSA 0. Checksum Sum 0x0 Number of DCbitless LSA 12 Number of indication LSA 0 Number of DoNotAge LSA 0 Flood list length 0
Examples 9-16, 9-17, and 9-18 present the Cisco IOS configurations of the hardy, laurel, and chaplin routers. These are straightforward standard OSPF configurations featuring a virtual link and different leaf-area types.
Example 9-16. Hardy Configuration and Diagnostic Output
hardy# sh running-config ... router ospf 1 router-id 192.168.201.3 log-adjacency-changes area 1 nssa redistribute connected subnets tag 1 redistribute static subnets tag 1 network 192.168.13.0 0.0.0.255 area 1 network 192.168.201.3 0.0.0.0 area 1 maximum-paths 2 ... hardy# sh ip ospf Routing Process "ospf 1" with ID 192.168.201.3 Supports only single TOS(TOS0) routes Supports opaque LSA It is an autonomous system boundary router Redistributing External Routes from, connected, includes subnets in redistribution static, includes subnets in redistribution SPF schedule delay 5 secs, Hold time between two SPFs 10 secs Minimum LSA interval 5 secs. Minimum LSA arrival 1 secs Number of external LSA 0. Checksum Sum 0x0 Number of opaque AS LSA 0. Checksum Sum 0x0 Number of DCbitless external and opaque AS LSA 0 Number of DoNotAge external and opaque AS LSA 0 Number of areas in this router is 1. 0 normal 0 stub 1 nssa External flood list length 0 Area 1 Number of interfaces in this area is 2 It is a NSSA area Area has no authentication SPF algorithm executed 9 times Area ranges are Number of LSA 13. Checksum Sum 0x7274B Number of opaque link LSA 0. Checksum Sum 0x0 Number of DCbitless LSA 0 Number of indication LSA 0 Number of DoNotAge LSA 0 Flood list length 0 hardy# sh ip ospf interface Loopback0 is up, line protocol is up Internet Address 192.168.201.3/32, Area 1 Process ID 1, Router ID 192.168.201.3, Network Type LOOPBACK, Cost: 1 Loopback interface is treated as a stub Host TokenRing0 is up, line protocol is up Internet Address 192.168.13.2/29, Area 1 Process ID 1, Router ID 192.168.201.3, Network Type BROADCAST, Cost: 6 Transmit Delay is 1 sec, State DR, Priority 1 Designated Router (ID) 192.168.201.3, Interface address 192.168.13.2 Backup Designated router (ID) 192.168.201.2, Interface address 192.168.13.1 Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:08 Index 1/1, flood queue length 0 Next 0x0(0)/0x0(0) Last flood scan length is 2, maximum is 2 Last flood scan time is 0 msec, maximum is 0 msec Neighbor Count is 1, Adjacent neighbor count is 1 Adjacent with neighbor 192.168.201.2 (Backup Designated Router) Suppress hello for 0 neighbor(s) hardy# sh ip ospf database OSPF Router with ID (192.168.201.3) (Process ID 1) Router Link States (Area 1) Link ID ADV Router Age Seq# Checksum Link count 192.168.201.2 192.168.201.2 516 0x80000019 0xCB5D 2 192.168.201.3 192.168.201.3 688 0x80000009 0x97E1 2 Net Link States (Area 1) Link ID ADV Router Age Seq# Checksum 192.168.13.2 192.168.201.3 688 0x80000005 0x67B5 Summary Net Link States (Area 1) Link ID ADV Router Age Seq# Checksum 192.168.1.0 192.168.201.2 262 0x80000008 0x4044 192.168.2.0 192.168.201.2 262 0x80000003 0x3554 192.168.7.0 192.168.201.2 778 0x80000018 0xC9A6 192.168.14.0 192.168.201.2 1541 0x8000001D 0x72F1 192.168.19.0 192.168.201.2 778 0x80000004 0xD19C 192.168.80.0 192.168.201.2 262 0x80000003 0xD763 192.168.201.1 192.168.201.2 778 0x80000004 0x932C 192.168.201.2 192.168.201.2 1541 0x80000011 0xBB0 192.168.201.4 192.168.201.2 778 0x80000004 0xD9D8 Type-7 AS External Link States (Area 1) Link ID ADV Router Age Seq# Checksum Tag 0.0.0.0 192.168.201.2 516 0x80000003 0x8876 0
Example 9-17. Chaplin Configuration and Diagnostic Output
chaplin# sh running-config ... router ospf 1 router-id 192.168.201.4 log-adjacency-changes area 5 virtual-link 192.168.1.1 area 5 virtual-link 192.168.201.2 area 7 stub no-summary passive-interface Serial0 passive-interface Serial1 network 192.168.19.0 0.0.0.255 area 5 network 192.168.201.4 0.0.0.0 area 7 maximum-paths 2 ... chaplin# sh ip ospf virtual-links Virtual Link OSPF_VL1 to router 192.168.1.1 is up Run as demand circuit DoNotAge LSA not allowed (Number of DCbitless LSA is 10). Transit area 5, via interface Ethernet0, Cost of using 20 Transmit Delay is 1 sec, State POINT_TO_POINT, Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:05 Adjacency State FULL Index 2/3, retransmission queue length 0, number of retransmission 2 First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0) Last retransmission scan length is 2, maximum is 2 Last retransmission scan time is 0 msec, maximum is 0 msec Virtual Link OSPF_VL0 to router 192.168.201.2 is up Run as demand circuit DoNotAge LSA not allowed (Number of DCbitless LSA is 10). Transit area 5, via interface Ethernet0, Cost of using 20 Transmit Delay is 1 sec, State POINT_TO_POINT, Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:05 Adjacency State FULL (Hello suppressed) Index 1/2, retransmission queue length 0, number of retransmission 3 First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0) Last retransmission scan length is 2, maximum is 2 Last retransmission scan time is 4 msec, maximum is 4 msec chaplin# sh ip ospf border-routers OSPF Process 1 internal Routing Table Codes: i - Intra-area route, I - Inter-area route i 192.168.44.1 [21] via 192.168.19.1, Ethernet0, ASBR, Area 0, SPF 14 i 192.168.1.1 [20] via 192.168.19.1, Ethernet0, ABR/ASBR, Area 0, SPF 14 i 192.168.1.1 [20] via 192.168.19.1, Ethernet0, ABR/ASBR, Area 5, SPF 5 i 192.168.201.2 [20] via 192.168.19.1, Ethernet0, ABR/ASBR, Area 0, SPF 14 i 192.168.201.2 [20] via 192.168.19.1, Ethernet0, ABR/ASBR, Area 5, SPF 5 i 192.168.201.1 [10] via 192.168.19.1, Ethernet0, ASBR, Area 5, SPF 5 i 192.168.2.7 [22] via 192.168.19.1, Ethernet0, ASBR, Area 0, SPF 14 chaplin# sh ip route Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area * - candidate default, U - per-user static route, o - ODR P - periodic downloaded static route Gateway of last resort is 192.168.19.1 to network 0.0.0.0 192.168.13.0/29 is subnetted, 1 subnets O IA 192.168.13.0 [110/26] via 192.168.19.1, 01:12:23, Ethernet0 O 192.168.14.0/24 [110/20] via 192.168.19.1, 01:12:23, Ethernet0 192.168.201.0/32 is subnetted, 4 subnets O 192.168.201.1 [110/11] via 192.168.19.1, 01:12:23, Ethernet0 O IA 192.168.201.3 [110/27] via 192.168.19.1, 01:12:23, Ethernet0 O 192.168.201.2 [110/21] via 192.168.19.1, 01:12:23, Ethernet0 C 192.168.201.4 is directly connected, Loopback0 O 192.168.80.0/24 [110/22] via 192.168.19.1, 01:12:23, Ethernet0 O E2 111.11.117.0/24 [110/1] via 192.168.19.1, 01:12:13, Ethernet0 O 192.168.7.0/24 [110/23] via 192.168.19.1, 01:12:23, Ethernet0 192.168.1.0/24 is variably subnetted, 4 subnets, 2 masks O E2 192.168.1.1/32 [110/1] via 192.168.19.1, 00:56:19, Ethernet0 O 192.168.1.0/24 [110/21] via 192.168.19.1, 01:12:23, Ethernet0 O E2 192.168.1.2/32 [110/1] via 192.168.19.1, 01:12:13, Ethernet0 O E2 192.168.1.254/32 [110/1] via 192.168.19.1, 01:12:13, Ethernet0 O 192.168.2.0/24 [110/22] via 192.168.19.1, 01:12:23, Ethernet0 C 192.168.19.0/24 is directly connected, Ethernet0 O*E2 0.0.0.0/0 [110/1] via 192.168.19.1, 01:12:13, Ethernet0 O IA 192.168.16.0/23 [110/26] via 192.168.19.1, 01:12:23, Ethernet0
Example 9-18. Laurel Configuration and Diagnostic Output
laurel# sh running-config ... router ospf 1 router-id 192.168.201.1 log-adjacency-changes redistribute connected subnets redistribute static subnets passive-interface Serial0 passive-interface Serial1 network 192.168.14.0 0.0.0.255 area 5 network 192.168.19.0 0.0.0.255 area 5 network 192.168.201.1 0.0.0.0 area 5 ... laurel# sh ip ospf Routing Process "ospf 1" with ID 192.168.201.1 and Domain ID 0.0.0.1 Supports only single TOS(TOS0) routes Supports opaque LSA It is an autonomous system boundary router Redistributing External Routes from, connected, includes subnets in redistribution static, includes subnets in redistribution SPF schedule delay 5 secs, Hold time between two SPFs 10 secs Minimum LSA interval 5 secs. Minimum LSA arrival 1 secs Number of external LSA 7. Checksum Sum 0x36FD1 Number of opaque AS LSA 0. Checksum Sum 0x0 Number of DCbitless external and opaque AS LSA 7 Number of DoNotAge external and opaque AS LSA 0 Number of areas in this router is 1. 1 normal 0 stub 0 nssa External flood list length 0 Area 5 Number of interfaces in this area is 3 Area has no authentication SPF algorithm executed 4 times Area ranges are Number of LSA 42. Checksum Sum 0x146F0A Number of opaque link LSA 0. Checksum Sum 0x0 Number of DCbitless LSA 12 Number of indication LSA 0 Number of DoNotAge LSA 0 Flood list length 0 laurel# sh ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 192.168.201.4 1 FULL/DR 00:00:38 192.168.19.2 Ethernet1 192.168.201.2 1 FULL/DR 00:00:30 192.168.14.254 Ethernet0 192.168.1.1 0 FULL/DROTHER 00:00:38 192.168.14.1 Ethernet0
Exercise 9-3: Exporting Loopback Addresses
Why does GateD not export/redistribute ganymed's lo1 interface address 192.168.44.1? If you figure it out, let me know.
Lab 9-5: Leaf-Area Design Featuring Zebra and Cisco IOS Software
This lab features the same topology as Lab 9-4 (Figure 9-3) with the difference that all UNIX gateways are running the Zebra zebra/ospfd now instead of GateD. However, they are implementing the same functionality.
NOTE
The configurations of the Cisco IOS routers are exactly as in Lab 9-4; therefore, they are omitted here.
Examples 9-19 to 9-21 present the Zebra ospfd configurations and relevant show commands for the three UNIX gateways callisto, castor, and ganymed. These examples also show the routing situation from the gateway's routing table point of view. Therefore, we can compare the OSPF RIB link-state database (LSDB) and the UNIX forwarding table.
Example 9-19. Zebra OSPF Configuration and Output on Callisto
[root@callisto:~#] telnet localhost 2604 Trying 127.0.0.1... Connected to localhost (127.0.0.1). Escape character is '^]'. Hello, this is zebra (version 0.94). Copyright 1996-2002 Kunihiro Ishiguro. User Access Verification Password: callisto-ospfd# show running-config Current configuration: ! hostname callisto-ospfd password 8 m6eyKycFMHniQ enable password 8 bjYlnA9YLBWyM log file /var/log/ospfd.log service advanced-vty service password-encryption ! interface lo ! interface eth0 ! interface eth1 ! interface ipsec0 ! interface ipsec1 ! interface ipsec2 ! interface ipsec3 ! interface eth1:1 ! interface lo1 ! router ospf ospf router-id 192.168.1.1 compatible rfc1583 redistribute connected redistribute static network 192.168.1.0/24 area 0 network 192.168.14.0/24 area 5 network 192.168.45.0/24 area 0 area 5 virtual-link 192.168.201.4 capability opaque ! access-list 1 remark vty-protection access-list 1 permit 127.0.0.1 access-list 1 permit 192.168.1.0 0.0.0.255 ! line vty access-class 1 exec-timeout 15 0 ! end callisto-ospfd# show ip ospf OSPF Routing Process, Router ID: 192.168.1.1 Supports only single TOS (TOS0) routes This implementation conforms to RFC2328 RFC1583Compatibility flag is enabled OpaqueCapability flag is enabled SPF schedule delay 5 secs, Hold time between two SPFs 10 secs Refresh timer 10 secs This router is an ABR, ABR type is: Standard (RFC2328) This router is an ASBR (injecting external routing information) Number of external LSA 3 Number of areas attached to this router: 2 Area ID: 0.0.0.0 (Backbone) Number of interfaces in this area: Total: 2, Active: 3 Number of fully adjacent neighbors in this area: 2 Area has no authentication SPF algorithm executed 12 times Number of LSA 29 Area ID: 0.0.0.5 Shortcutting mode: Default, S-bit consensus: no Number of interfaces in this area: Total: 1, Active: 2 Number of fully adjacent neighbors in this area: 2 Area has no authentication Number of full virtual adjacencies going through this area: 1 SPF algorithm executed 12 times Number of LSA 35 callisto-ospfd# show ip ospf interface lo is up, line protocol is up OSPF not enabled on this interface eth0 is up, line protocol is up Internet Address 192.168.14.1/24, Area 0.0.0.5 Router ID 192.168.1.1, Network Type BROADCAST, Cost: 10 Transmit Delay is 1 sec, State DR, Priority 1 Designated Router (ID) 192.168.1.1, Interface Address 192.168.14.1 Backup Designated Router (ID) 192.168.201.2, Interface Address 192.168.14.254 Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:04 Neighbor Count is 2, Adjacent neighbor count is 2 eth1 is up, line protocol is up Internet Address 192.168.1.1/24, Area 0.0.0.0 Router ID 192.168.1.1, Network Type BROADCAST, Cost: 10 Transmit Delay is 1 sec, State Backup, Priority 1 Designated Router (ID) 192.168.1.254, Interface Address 192.168.1.254 Backup Designated Router (ID) 192.168.1.1, Interface Address 192.168.1.1 Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:09 Neighbor Count is 1, Adjacent neighbor count is 1 ipsec0 is up, line protocol is up OSPF not enabled on this interface ipsec1 is down, line protocol is down OSPF not enabled on this interface ipsec2 is down, line protocol is down OSPF not enabled on this interface ipsec3 is down, line protocol is down OSPF not enabled on this interface eth1:1 is down, line protocol is down OSPF not enabled on this interface lo1 is down, line protocol is down OSPF not enabled on this interface VLINK0 is up, line protocol is up Internet Address 192.168.14.1/24, Area 0.0.0.0 Router ID 192.168.1.1, Network Type VIRTUALLINK, Cost: 20 Transmit Delay is 1 sec, State Point-To-Point, Priority 1 No designated router on this network No backup designated router on this network Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:09 Neighbor Count is 1, Adjacent neighbor count is 1 callisto-ospfd# show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface RXmtL RqstL
Note that one static route, 172.16.7.0/24, has been added to demonstrate administrative distance assignment to a route in Example 9-20.
Example 9-20. Zebra OSPF Configuration and Output on Castor
[root@castor:~#] netstat -rn -f inet Routing tables Internet: Destination Gateway Flags Refs Use Netif Expire default 192.168.2.254 UGSc 2 0 xl0 127.0.0.1 127.0.0.1 UH 0 4154 lo0 172.16.7/24 link#1 UC1 0 0 xl0 192.168.1 192.168.2.254 UG1c 1 99 xl0 192.168.2 link#1 UC 1 0 xl0 192.168.2.254 52:54:05:e3:e4:2f UHLW 7 96 xl0 1162 192.168.7 link#2 UC 1 0 ed0 192.168.7.254 00:00:0c:1a:a9:a8 UHLW 10 219 ed0 522 192.168.13/29 192.168.7.254 UG1c 0 3 ed0 192.168.14 192.168.7.254 UG1c 0 0 ed0 192.168.16/23 192.168.7.254 UG1c 0 0 ed0 192.168.19 192.168.7.254 UG1c 0 0 ed0 192.168.44 192.168.2.254 UG1c 0 0 xl0 192.168.80 link#14 UC 1 0 vlan8 192.168.80.254 52.54.5.e3.e4.2f UHLW 0 0 vlan8 264 192.168.201.1 192.168.7.254 UGH1 0 0 ed0 192.168.201.2 192.168.7.254 UGH1 0 0 ed0 192.168.201.3 192.168.7.254 UGH1 0 80 ed0 192.168.201.4 192.168.7.254 UGH1 0 0 ed0 111.11.117 192.168.2.254 UG1c 0 0 xl0 [root@castor:~#] telnet localhost 2601 Trying 127.0.0.1... Connected to localhost.nerdzone.org. Escape character is '^]'. Hello, this is zebra (version 0.93a). Copyright 1996-2002 Kunihiro Ishiguro. User Access Verification Password: castor-zebra# show running-config Current configuration: ! hostname castor-zebra password 8 bJFoEOB0obLL6 enable password 8 4DwwIFdKLWvU. log file /var/log/zebra.log service advanced-vty service password-encryption ! interface xl0 ip address 192.168.2.7/24 multicast ipv6 nd suppress-ra ! interface ed0 ip address 192.168.7.7/24 multicast ipv6 nd suppress-ra ! interface lp0 ipv6 nd suppress-ra ! interface ppp0 ipv6 nd suppress-ra ! interface ppp1 ipv6 nd suppress-ra ! interface sl0 ipv6 nd suppress-ra ! interface sl1 ipv6 nd suppress-ra ! interface ds0 ! interface stf0 ipv6 nd suppress-ra ! interface faith0 ipv6 nd suppress-ra ! interface vlan0 ipv6 nd suppress-ra ! interface vlan1 ipv6 nd suppress-ra ! interface lo0 ! interface vlan8 multicast ipv6 nd suppress-ra ! interface gif0 ipv6 nd suppress-ra ! ip route 172.16.7.0/24 xl0 22 ! access-list 1 remark vty-protection access-list 1 permit 127.0.0.1 access-list 1 permit 192.168.1.0 0.0.0.255 ! ! line vty access-class 1 exec-timeout 15 0 ! end castor-zebra# show ip route Codes: K - kernel route, C - connected, S - static, R - RIP, O - OSPF, I - IS-IS, B - BGP, > - selected route, * - FIB route K>* 0.0.0.0/0 via 192.168.2.254, xl0 C>* 127.0.0.0/8 is directly connected, lo0 S>* 172.16.7.0/24 [22/0] is directly connected, xl0 O>* 192.168.1.0/24 [110/20] via 192.168.2.254, xl0, 01:28:22 * via 192.168.80.254, vlan8, 01:28:22 O 192.168.2.0/24 [110/10] is directly connected, xl0, 01:28:22 C>* 192.168.2.0/24 is directly connected, xl0 O 192.168.7.0/24 [110/10] is directly connected, ed0, 01:28:32 C>* 192.168.7.0/24 is directly connected, ed0 O>* 192.168.13.0/29 [110/16] via 192.168.7.254, ed0, 01:27:31 O>* 192.168.14.0/24 [110/20] via 192.168.7.254, ed0, 01:27:41 O>* 192.168.16.0/23 [110/16] via 192.168.7.254, ed0, 01:27:21 O>* 192.168.19.0/24 [110/30] via 192.168.7.254, ed0, 01:26:27 O>* 192.168.44.0/24 [110/20] via 192.168.2.254, xl0, 01:28:21 * via 192.168.80.254, vlan8, 01:28:21 O 192.168.80.0/24 [110/10] is directly connected, vlan8, 01:28:22 C>* 192.168.80.0/24 is directly connected, vlan8 O>* 192.168.201.1/32 [110/21] via 192.168.7.254, ed0, 01:26:27 O>* 192.168.201.2/32 [110/11] via 192.168.7.254, ed0, 01:27:41 O>* 192.168.201.3/32 [110/17] via 192.168.7.254, ed0, 01:27:31 O>* 192.168.201.4/32 [110/31] via 192.168.7.254, ed0, 01:26:07 O>* 111.11.117.0/24 [110/20] via 192.168.2.254, xl0, 01:28:21 * via 192.168.80.254, vlan8, 01:28:21 [root@castor:~#] telnet localhost 2604 Trying 127.0.0.1... Connected to localhost.nerdzone.org. Escape character is '^]'. Hello, this is zebra (version 0.93a). Copyright 1996-2002 Kunihiro Ishiguro. User Access Verification Password: castor-ospfd# show running-config Current configuration: ! hostname castor-ospfd password 8 4DwwIFdKLWvU. enable password 8 dV8x4MhxDAuaw log file /var/log/ospfd.log service advanced-vty service password-encryption ! interface xl0 ! interface ed0 ! interface lp0 ip ospf network point-to-point ! interface sl0 ip ospf network point-to-point ! interface sl1 ip ospf network point-to-point ! interface ds0 ! interface stf0 ! interface faith0 ! interface vlan0 ! interface vlan1 ! interface lo0 ! interface ppp0 ip ospf network point-to-point ! interface ppp1 ip ospf network point-to-point ! interface vlan8 ! interface lo1 ! router ospf ospf router-id 192.168.2.7 compatible rfc1583 redistribute connected redistribute static network 192.168.2.0/24 area 0 network 192.168.7.0/24 area 0 network 192.168.80.0/24 area 0 capability opaque ! access-list 1 remark vty-protection access-list 1 permit 127.0.0.1 access-list 1 permit 192.168.1.0 0.0.0.255 ! line vty access-class 1 exec-timeout 15 0 ! end castor-ospfd# show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface
Example 9-21. Zebra OSPF Configuration and Output on Ganymed
ganymed-ospfd# show running-config ... router ospf ospf router-id 192.168.1.254 compatible rfc1583 redistribute connected redistribute static network 192.168.1.0/24 area 0 network 192.168.2.0/24 area 0 network 192.168.45.0/24 area 0 network 192.168.80.0/24 area 0 capability opaque ... [root@ganymed:~#] netstat -rn -f inet Routing tables Internet: Destination Gateway Flags Refs Use Mtu Interface default 111.11.117.1 UGS 1 8314 1500 ne5 127/8 127.0.0.1 UGRS 0 0 33224 lo0 127.0.0.1 127.0.0.1 UH 4 714 33224 lo0 172.16.7/24 192.168.2.7 UG1 0 0 1500 ne4 192.168.1/24 link#1 UC 0 0 1500 ne3 192.168.1.1 52:54:5:e3:51:87 UHL 5 2806 1500 ne3 192.168.1.2 8:0:46:64:74:1b UHL 1 11211 1500 ne3 192.168.1.254 127.0.0.1 UGHS 0 0 33224 lo0 192.168.2/24 link#2 UC 0 0 1500 ne4 192.168.2.7 0:10:5a:c4:2c:4 UHL 6 6466 1500 ne4 192.168.7/24 192.168.2.7 UG1 1 130 1500 ne4 192.168.13.0/29 192.168.2.7 UG1 0 3 1500 ne4 192.168.14/24 192.168.1.1 UG1 0 0 1500 ne3 192.168.16/23 192.168.2.7 UG1 0 0 1500 ne4 192.168.19/24 192.168.1.1 UG1 0 0 1500 ne3 192.168.44.1 192.168.44.1 UH 0 0 33224 lo1 192.168.80/24 link#16 UC 0 0 1496 vlan0 192.168.80.1 0:10:5a:c4:2c:4 UHL 0 0 1496 vlan0 192.168.201.1 192.168.1.1 UGH1 0 0 1500 ne3 192.168.201.2 192.168.2.7 UGH1 0 0 1500 ne4 192.168.201.3 192.168.2.7 UGH1 1 87 1500 ne4 192.168.201.4 192.168.1.1 UGH1 0 1 1500 ne3 111.11.117/24 link#3 UC 0 0 1500 ne5 111.11.117.1 0:5:9a:5b:23:fc UHL 1 0 1500 ne5 ganymed-zebra# sh ip route Codes: K - kernel route, C - connected, S - static, R - RIP, O - OSPF, B - BGP, > - selected route, * - FIB route K>* 0.0.0.0/0 via 111.11.117.1, ne5 K * 127.0.0.0/8 via 127.0.0.1 inactive C>* 127.0.0.0/8 is directly connected, lo0 O>* 172.16.7.0/24 [110/20] via 192.168.2.7, ne4, 01:35:14 * via 192.168.80.1, vlan0, 01:35:14 O 192.168.1.0/24 [110/10] is directly connected, ne3, 01:50:01 C>* 192.168.1.0/24 is directly connected, ne3 O 192.168.2.0/24 [110/10] is directly connected, ne4, 01:50:00 C>* 192.168.2.0/24 is directly connected, ne4 O>* 192.168.7.0/24 [110/20] via 192.168.2.7, ne4, 01:35:15 * via 192.168.80.1, vlan0, 01:35:15 O>* 192.168.13.0/29 [110/26] via 192.168.2.7, ne4, 01:34:25 * via 192.168.80.1, vlan0, 01:34:25 O>* 192.168.14.0/24 [110/20] via 192.168.1.1, ne3, 01:40:11 O>* 192.168.16.0/23 [110/26] via 192.168.2.7, ne4, 01:34:15 * via 192.168.80.1, vlan0, 01:34:15 O>* 192.168.19.0/24 [110/30] via 192.168.1.1, ne3, 01:33:11 C>* 192.168.44.0/24 is directly connected, lo1 O 192.168.80.0/24 [110/10] is directly connected, vlan0, 01:35:15 C>* 192.168.80.0/24 is directly connected, vlan0 O>* 192.168.201.1/32 [110/21] via 192.168.1.1, ne3, 01:33:11 O>* 192.168.201.2/32 [110/21] via 192.168.2.7, ne4, 01:34:35 * via 192.168.80.1, vlan0, 01:34:35 O>* 192.168.201.3/32 [110/27] via 192.168.2.7, ne4, 01:34:25 * via 192.168.80.1, vlan0, 01:34:25 O>* 192.168.201.4/32 [110/31] via 192.168.1.1, ne3, 01:33:01 C>* 111.11.117.0/24 is directly connected, ne5 ganymed-ospfd# show ip ospf OSPF Routing Process, Router ID: 192.168.1.254 Supports only single TOS (TOS0) routes This implementation conforms to RFC2328 RFC1583Compatibility flag is enabled OpaqueCapability flag is enabled SPF schedule delay 5 secs, Hold time between two SPFs 10 secs Refresh timer 10 secs This router is an ASBR (injecting external routing information) Number of external LSA 3 Number of areas attached to this router: 1 Area ID: 0.0.0.0 (Backbone) Number of interfaces in this area: Total: 3, Active: 6 Number of fully adjacent neighbors in this area: 3 Area has no authentication SPF algorithm executed 15 times Number of LSA 29 ganymed-ospfd# show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface
ECMP—Manipulating Metric and Distance
ECMP is a capability of the underlying operating system. It can be achieved via equal-cost static routes independently of dynamic routing protocols. Still, the question arises whether the resulting load-sharing behavior is packet-based or flow-based.
NOTE
Link-state protocols such as OSPF and IS-IS were designed to support ECMP, depending on the implementation. GateD is capable of ECMP; however, you must alter the MULTIPATH definition in the sources to enable this feature (see Example 9-22). In my GateD lab, ECMP is disabled.
Example 9-22. GateD ECMP Configuration
./gated-public-3_6/src/gated/rt_table.h:
/*
* The number of multipath routes supported by the forwarding engine.
*/
#ifndef RT_N_MULTIPATH
#define RT_N_MULTIPATH 6
#endif /* RT_N_MULTIPATH */
Zebra ospfd is capable of ECMP as well; isisd is not yet capable of ECMP. Including ECMP support has to be decided at compile time (configure --enable-multipath=6). It is highly recommended that you read the ECMP RFCs (RFC 2991 and RFC 2992) for a better grasp of this delicate matter.
Keep in mind that load balancing is done only on outbound traffic; be aware of what really resembles a flow when testing your setup, so as not to misjudge the behavior of a correct configuration! Example 9-23 shows an example combination of the ECMP-capable Linux kernel and the Zebra ospfd.
Example 9-23. Linux ECMP in Action
[root@callisto:~#] ip route 192.168.201.2 via 192.168.14.254 dev eth0 proto zebra metric 11 equalize 192.168.17.0/29 via 192.168.14.254 dev eth0 proto zebra metric 16 equalize 192.168.13.0/29 via 192.168.14.254 dev eth0 proto zebra metric 16 equalize 192.168.7.0/24 via 192.168.14.254 dev eth0 proto zebra metric 20 equalize 111.11.117.0/24 via 192.168.1.254 dev eth1 proto zebra metric 20 equalize 192.168.2.0/24 via 192.168.1.254 dev eth1 proto zebra metric 20 equalize 192.168.80.0/24 via 192.168.1.254 dev eth1 proto zebra metric 20 equalize 192.168.1.0/24 dev eth1 scope link 192.168.201.0/24 proto zebra metric 20 equalize nexthop via 192.168.14.254 dev eth0 weight 1 nexthop via 192.168.1.254 dev eth1 weight 1 192.168.14.0/24 dev eth0 scope link 192.168.44.0/24 via 192.168.1.254 dev eth1 proto zebra metric 20 equalize 192.168.45.0/24 via 192.168.1.254 dev eth1 proto zebra metric 20 equalize 127.0.0.0/8 dev lo scope link default via 192.168.1.254 dev eth1
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