Maipu Administration Guide

Configure IRMP Metric Offset

Network Requirements

The IRMP protocol operates among Device1, Device2, Device3, and Device4 for interconnection.
Device1 learns the routing 200.0.0.0/24 from Device2 and Device3 at the same time.
Configure the routing metric offset at the receiving direction on Device1to enable Device1 to choose the routing advertised by Device2 preferentially.

Network Topology

Networking of the IRMP metric offset

Figure 11–3 Networking of the IRMP metric offset

Configuration Steps

Step 1: Configure the IP address of the interfaces. (Omitted)

Step 2: Configure the IRMP.

#Configure Device1.

Device1#configure terminal
Device1(config)#router irmp 100
Device1(config-irmp)#network 1.0.0.0 0.0.0.255
Device1(config-irmp)#network 2.0.0.0 0.0.0.255
Device1(config-irmp)#exit

#Configure Device2.

Device2#configure terminal
Device2(config)#router irmp 100
Device2(config-irmp)#network 1.0.0.0 0.0.0.255
Device2(config-irmp)#network 3.0.0.0 0.0.0.255
Device2(config-irmp)#exit

#Configure Device3.

Device3#configure terminal
Device3(config)#router irmp 100
Device3(config-irmp)#network 2.0.0.0 0.0.0.255
Device3(config-irmp)#network 4.0.0.0 0.0.0.255
Device3(config-irmp)#exit

#Configure Device4.

Device4#configure terminal
Device4(config)#router irmp 100
Device4(config-irmp)#network 3.0.0.0 0.0.0.255
Device4(config-irmp)#network 4.0.0.0 0.0.0.255
Device4(config-irmp)#network 200.0.0.0 0.0.0.255
Device4(config-irmp)#exit

#View the IRMP neighbor inofrmation of Device1.

Device1#show ip irmp neighbor  
IP-IRMP neighbors for process 100 Total neighbor 2 
Address     Interface            Hold(s) Uptime   SeqNum   Srtt(ms) Rto(s) 
1.0.0.2     gigabitethernet0     11      00:10:37 10       0        2       
2.0.0.2     gigabitethernet1     12      00:10:15 9        0        2

#View the IRMP neighbor information of Device4.

Device4#show ip irmp neighbor  
IP-IRMP neighbors for process 100 Total neighbor 2 
Address     Interface            Hold(s) Uptime   SeqNum   Srtt(ms) Rto(s) 
3.0.0.1     gigabitethernet1     14      00:11:37 13       0        2       
4.0.0.1     gigabitethernet2     12      00:10:45 12       0        2

Device1 successfully establishes the IRMP neighbor with Device2 and Device3, respectively. Device4 successfully establishes the IRMP neighbor with Device2 and Device3, respectively.

#View the topology table and routing table of Device1.

Device1#show ip irmp topology  
IP-IRMP Topology Table for process 100 
Codes: P - Passive, A - Active, H - Holddown, D - Hidden 
        > - FIB route, * - FIB successor 
 
P >1.0.0.0/24, 1 successors, FD is 2816 
        *via Connected (2816/0), gigabitethernet0
P >2.0.0.0/24, 1 successors, FD is 2816 
        *via Connected (2816/0), gigabitethernet1
P >3.0.0.0/24, 1 successors, FD is 3072 
        *via 1.0.0.2 (3072/2816), gigabitethernet0
P >4.0.0.0/24, 1 successors, FD is 3072 
        *via 2.0.0.2 (3072/512), gigabitethernet1
P >200.0.0.0/24, 2 successors, FD is 3328 
        *via 2.0.0.2 (3328/3072), gigabitethernet1 
        *via 1.0.0.2 (3328/3072), gigabitethernet0 
 
Device1#show ip route 
Codes: C - connected, S - static, R - RIP, O - OSPF, OE-OSPF External, M - Management 
       D - Redirect, E - IRMP, EX - IRMP external, o - SNSP, B - BGP, i-ISIS  
 
Gateway of last resort is not set 
 
C 1.0.0.0/24 is directly connected, 13:16:35, gigabitethernet0 
C 2.0.0.0/24 is directly connected, 13:19:24, gigabitethernet1
E 3.0.0.0/24 [90/3072] via 1.0.0.2, 00:03:22, gigabitethernet0
E 4.0.0.0/24 [90/3072] via 2.0.0.2, 00:22:01, gigabitethernet1
C 127.0.0.0/8 is directly connected, 22:27:25, lo0 
E 200.0.0.0/24 [90/3328] via 2.0.0.2, 00:21:22, gigabitethernet1 
                 [90/3328] via 1.0.0.2, 00:03:22, gigabitethernet0

There are two load balancing routing to the network segment 200.0.0.0/24 in Device1 routing table. The forwarding paths to the network segment are Device1→ Device2→ Device4 and Device1→ Device3→ Device4.

Step 3: Configure the IRMP metric offset.

#Configure the offset list on Device1. Add metric value 100 to the interface connected to Device3 by the specified routing to enable the total metric value going through Device3 is larger than that going through Device2.

Device1(config)#ip access-list standard 1
Device1(config-std-nacl)#permit 200.0.0.0 0.0.0.255
Device1(config-std-nacl)#exit
Device1(config)#router irmp 100
Device1(config-irmp)#offset-list 1 in 100 gigabitethernet1
Device1(config-irmp)#exit

Step 4: Check the result.