Most Cisco documents state that networks and interfaces are added to the EIGRP routing process in NX-OS using the interface configuration mode. The Cisco NX-OS/IOS EIGRP Comparison page states this, so do the Configuring EIGRP pages in the Cisco Nexus 7000 Series NX-OS Unicast Routing Configuration Guide, Release 5.x documentation. These commands work fine. However, I recently found that this is not the only way to configure EIGRP on the Nexus 7000.
One of my customers asked me to look over his EIGRP configuration. He had two IP interfaces configured on SVIs:
N7K1# sh ip int brie IP Interface Status for VRF "default"(1) Interface IP Address Interface Status Vlan5 10.13.5.252 protocol-up/link-up/admin-up Vlan24 10.13.24.8 protocol-up/link-up/admin-up N7K1#
The VLANs were running on port-channels on a N7K-M108X2-12L (10 Gbps Ethernet XL Module) and a N7K-M148GS-11L (1000 Mbps Optical Ethernet XL Module.) He had three EIGRP neighbors on VLAN 24:
N7K1# sh ip eigrp nei IP-EIGRP neighbors for process 100 VRF default H Address Interface Hold Uptime SRTT RTO Q Seq (sec) (ms) Cnt Num 2 10.13.24.10 vlan24 10 2w3d 1 200 0 149 1 10.13.24.11 vlan24 11 2w3d 1 200 0 120 0 10.13.24.9 vlan24 11 2w3d 1 200 0 18 N7K1#
Only VLAN 24 was an EIGRP interface:
N7K1# sh ip eigrp int brie IP-EIGRP interfaces for process 100 VRF default Xmit Queue Mean Pacing Time Multicast Pending Interface Peers Un/Reliable SRTT Un/Reliable Flow Timer Routes vlan24 3 0/0 1 0/1 50 0 N7K1#
I then noticed he had implemented EIGRP the ‘old fashioned’ way, and had configured network statements under the EIGRP routing process:
N7K1# sh run eigrp !Command: show running-config eigrp !Time: Wed Nov 23 11:00:00 2011 version 5.1(4) feature eigrp router eigrp 100 network 10.0.0.0/8 interface Vlan5 ip passive-interface eigrp 100 N7K1#
I also checked his interface configuration:
N7K1# sh run int vlan5, vlan 24 !Command: show running-config interface Vlan5, Vlan24 !Time: Fri Nov 23 11:13:38 2011 version 5.1(4) interface Vlan5 no ip redirects ip address 10.13.5.252/24 ip passive-interface eigrp 100 hsrp version 2 hsrp 5 preempt delay minimum 60 priority 110 timers 1 3 ip 10.13.5.254 no shutdown interface Vlan24 no ip redirects ip address 10.13.24.8/24 no shutdown N7K1#
What I learned – at least with some versions of NX-OS, you can configure EIGRP using network commands under the routing process.
In any case, I prefer using interface commands to configure EIGRP in NX-OS – I think it allows you more control. Based on the Cisco documentation, it appears to be the supported mechanism so if you have to call TAC it is probably what they expect to see.
More on Nexus Design and Configuration
For more information on Nexus designs, you may want to review the following articles:
- Configuring Back-to-Back vPCs on Cisco Nexus Switches
- The Nexus 5000 and Nexus 2000: Tidbits and Gotchas
- Designing with the Nexus 5000 / 2000
- Designing VPC and Routing
- QoS on the Nexus 5000/2000 – Part 1
- (Configuring) QoS on the Nexus 5000/2000 – Part 2
- Trust Boundaries and QoS on the Nexus 5000/2000 – Part 3