Nexus 93180 not propagating network through EIGRP

[igor.hamzic81]

Hello all. I have a rather strange problem regarding the EIGRP on Nexus 93180 switches.

The simplified net topology pic is attached.

All locations are using EIGRP for routing and using the same AS number. A pair of Nexus switches(connected via VPC link) are in each DC and are part of the same L2 domain(they have the same VLANs on them, L3 VLAN interfaces with different IPs from the same subnet on them, they are connected through MPLS between DC locations).

The problem that I see is that the user network from user location 2 the for  is only seen through 3850 switch in user location 1 over the direct link to user location 2. No matter what I do the network is not also seen through Nexus 93180-2 in DC 2 which has a direct link to user location 2. The Nexus 93180-2 in DC 2 has a route to the network in it's routing and topology tables but is not propagating it to the rest of the network.

The frustrating thing is that the Nexus 93180-2 in DC 2 sees the route to user network 1 in the topology table from other Nexus switches and through the 3850 switch in user location 2. 3850 switch in user location 2 also sees the user network in the topology table from user location 1 both from the Nexus 93180-2 in DC 2 and from the 3850 switch in user location 1.

I would be grateful for any help in why the Nexus 93180-2 in DC 2 is not propagating the route for user network 2 to the rest of the network.

[MHM Cisco World]

This MPLS abd backdoor connect' it seem that NSK prefer path via backdoor not via mpls' Am I right?

MHM

[igor.hamzic81]

Not quite. Even though Nexus 93180-2 in DC 2 has the user network in location 2 in both routing and topology table that info is not seen on no other device. For example there is no entry in the topology table in Nexus 93180-1 in DC 2, Nexus 93180-1 in DC 1, Nexus 93180-2 in DC 1 or 3850 switch in user location 1.

[balaji.bandi]

wht is the vPC domain ID of both the sides ? do you have peer router and peet gateway configure - can you post show vpc output here.

can you post from all device show routing table (for that learning routes related to user location 1 and location 2) also eigrp neighur ship relation.

[igor.hamzic81]

These is the VPC info for the Nexus switches.

Nexus 93180-1 in DC 1

vPC domain id : 300
Peer status : peer adjacency formed ok
vPC keep-alive status : peer is alive
Configuration consistency status : success
Per-vlan consistency status : success
Type-2 consistency status : failed
Type-2 inconsistency reason : SVI type-2 configuration incompatible
vPC role : primary
Number of vPCs configured : 212
Peer Gateway : Enabled
Dual-active excluded VLANs : -
Graceful Consistency Check : Enabled
Auto-recovery status : Disabled
Delay-restore status : Timer is off.(timeout = 150s)
Delay-restore SVI status : Timer is off.(timeout = 10s)
Operational Layer3 Peer-router : Enabled
Virtual-peerlink mode : Disabled

vpc domain 300
role priority 90
peer-keepalive destination 192.168.169.254 source 192.168.169.253
delay restore 150
peer-gateway
layer3 peer-router
ip arp synchronize

Nexus 93180-2 in DC 1

vPC domain id : 300
Peer status : peer adjacency formed ok
vPC keep-alive status : peer is alive
Configuration consistency status : success
Per-vlan consistency status : success
Type-2 consistency status : failed
Type-2 inconsistency reason : SVI type-2 configuration incompatible
vPC role : secondary
Number of vPCs configured : 212
Peer Gateway : Enabled
Dual-active excluded VLANs : -
Graceful Consistency Check : Enabled
Auto-recovery status : Disabled
Delay-restore status : Timer is off.(timeout = 150s)
Delay-restore SVI status : Timer is off.(timeout = 10s)
Operational Layer3 Peer-router : Enabled
Virtual-peerlink mode : Disabled

vpc domain 300
role priority 90
peer-keepalive destination 192.168.169.253 source 192.168.169.254
delay restore 150
peer-gateway
layer3 peer-router
ip arp synchronize

Nexus 93180-1 in DC 2

vPC domain id : 400
Peer status : peer adjacency formed ok
vPC keep-alive status : peer is alive
Configuration consistency status : success
Per-vlan consistency status : success
Type-2 consistency status : success
vPC role : primary
Number of vPCs configured : 8
Peer Gateway : Enabled
Dual-active excluded VLANs : -
Graceful Consistency Check : Enabled
Auto-recovery status : Disabled
Delay-restore status : Timer is off.(timeout = 150s)
Delay-restore SVI status : Timer is off.(timeout = 10s)
Operational Layer3 Peer-router : Enabled
Virtual-peerlink mode : Disabled

vpc domain 400
role priority 100
peer-keepalive destination 192.168.169.253 source 192.168.169.254
delay restore 150
peer-gateway
layer3 peer-router
ip arp synchronize

Nexus 93180-2 in DC 2

vPC domain id : 400
Peer status : peer adjacency formed ok
vPC keep-alive status : peer is alive
Configuration consistency status : success
Per-vlan consistency status : success
Type-2 consistency status : success
vPC role : secondary
Number of vPCs configured : 8
Peer Gateway : Enabled
Dual-active excluded VLANs : -
Graceful Consistency Check : Enabled
Auto-recovery status : Disabled
Delay-restore status : Timer is off.(timeout = 150s)
Delay-restore SVI status : Timer is off.(timeout = 10s)
Operational Layer3 Peer-router : Enabled
Virtual-peerlink mode : Disabled

vpc domain 400
role priority 100
peer-keepalive destination 192.168.169.254 source 192.168.169.253
delay restore 150
peer-gateway
layer3 peer-router
ip arp synchronize

Nexus 93180-1 in DC 1

EIGRP neighbors - relevant ones

IP-EIGRP neighbors for process 77 VRF default
H Address Interface Hold Uptime SRTT RTO Q Seq
(sec) (ms) Cnt Num
18 10.64.3.3 Vlan3 11 18w3d 1 50 0 18797 -> Nexus 93180-2 in DC 1
3 10.64.3.4 Vlan3 12 18w4d 1 50 0 2555 -> Nexus 93180-1 in DC 2
4 10.64.3.5 Vlan3 11 18w4d 1 50 0 2593 -> Nexus 93180-2 in DC 2
12 10.254.2.1 Vlan720 14 18w3d 1 50 0 10267 -> 3850 in user location 1

Routing table

#sh ip route 10.65.196.0
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%<string>' in via output denotes VRF <string>

10.65.196.0/23, ubest/mbest: 1/0
*via 10.254.2.1, Vlan720, [90/3072], 18w3d, eigrp-Core_routing, internal

#sh ip route 10.64.16.0
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%<string>' in via output denotes VRF <string>

10.64.16.0/23, ubest/mbest: 1/0
*via 10.254.2.1, Vlan720, [90/3328], 13:05:00, eigrp-Core_routing, internal

Nexus 93180-2 in DC 1

EIGRP neighbors - relevant ones

IP-EIGRP neighbors for process 77 VRF default
H Address Interface Hold Uptime SRTT RTO Q Seq
(sec) (ms) Cnt Num
1 10.64.3.2 Vlan3 10 18w3d 1 50 0 19461 -> Nexus 93180-1 in DC 1
0 10.64.3.4 Vlan3 13 18w3d 1 50 0 2554 -> Nexus 93180-1 in DC 2
2 10.64.3.5 Vlan3 12 18w3d 1 50 0 2592 -> Nexus 93180-2 in DC 2
14 10.254.2.1 Vlan720 10 18w3d 1 50 0 10264 -> 3850 in user location 1

Routing table

#sh ip route 10.65.196.0
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%<string>' in via output denotes VRF <string>

10.65.196.0/23, ubest/mbest: 1/0
*via 10.254.2.1, Vlan720, [90/3072], 18w3d, eigrp-Core_routing, internal

# sh ip route 10.64.16.0
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%<string>' in via output denotes VRF <string>

10.64.16.0/23, ubest/mbest: 1/0
*via 10.254.2.1, Vlan720, [90/3328], 13:09:12, eigrp-Core_routing, internal

Nexus 93180-1 in DC 2

EIGRP neighbors - relevant ones

IP-EIGRP neighbors for process 77 VRF default
H Address Interface Hold Uptime SRTT RTO Q Seq
(sec) (ms) Cnt Num
3 10.64.3.2 Vlan3 13 18w4d 1 50 0 19461 -> Nexus 93180-1 in DC 1
4 10.64.3.3 Vlan3 11 18w4d 1 50 0 18788 -> Nexus 93180-2 in DC 1
2 10.64.3.5 Vlan3 10 20w1d 1 50 0 2591 -> Nexus 93180-2 in DC 2

Routing table

# sh ip route 10.65.196.0
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%<string>' in via output denotes VRF <string>

10.65.196.0/23, ubest/mbest: 2/0
*via 10.64.3.2, Vlan3, [90/3328], 18w3d, eigrp-Core_routing, internal
*via 10.64.3.3, Vlan3, [90/3328], 18w3d, eigrp-Core_routing, internal

Nexus 93180-2 in DC 2

EIGRP neighbors - relevant ones

IP-EIGRP neighbors for process 77 VRF default
H Address Interface Hold Uptime SRTT RTO Q Seq
(sec) (ms) Cnt Num
3 10.64.3.2 Vlan3 12 18w4d 1 50 0 19461 -> Nexus 93180-1 in DC 1
4 10.64.3.3 Vlan3 14 18w4d 1 50 0 18788 -> Nexus 93180-2 in DC 1
1 10.64.3.4 Vlan3 11 20w1d 1 50 0 2553 -> Nexus 93180-1 in DC 2
0 192.168.20.10 Eth1/31 14 12:01:43 2 50 0 10475 -> 3850 in user location 2

Routing table

# sh ip route 10.65.196.0
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%<string>' in via output denotes VRF <string>

10.65.196.0/23, ubest/mbest: 2/0
*via 10.64.3.2, Vlan3, [90/3328], 18w3d, eigrp-Core_routing, internal
*via 10.64.3.3, Vlan3, [90/3328], 18w3d, eigrp-Core_routing, internal

# sh ip route 10.64.16.0 -> take note that the route is pointing to Nexus switches in DC1 as I had to increase delay on the interface towards 3850 switch on location 2 as the users where experiencing problems when traffic tried going to this network using directly attached link; quick fix to resolve user connectivity problems in user location 2
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%<string>' in via output denotes VRF <string>

10.64.16.0/23, ubest/mbest: 2/0
*via 10.64.3.2, Vlan3, [90/3584], 07:53:38, eigrp-Core_routing, internal
*via 10.64.3.3, Vlan3, [90/3584], 07:53:38, eigrp-Core_routing, internal

3850 in user location 1

EIGRP neighbors

EIGRP-IPv4 Neighbors for AS(77)
H Address Interface Hold Uptime SRTT RTO Q Seq
(sec) (ms) Cnt Num
3 10.254.2.3 Te2/1/4 10 18w3d 1 100 0 18791 -> Nexus 93180-2 in DC 1
2 10.254.2.2 Te2/1/4 12 18w3d 1 100 0 19459 -> Nexus 93180-1 in DC 1
0 10.254.1.2 Gi1/0/1 14 2y20w 1 100 0 10477 -> 3850 in user location 2

Routing table

#sh ip route 10.65.196.0
Routing entry for 10.65.196.0/23
Known via "connected", distance 0, metric 0 (connected, via interface)
Redistributing via eigrp 77
Routing Descriptor Blocks:
* directly connected, via Vlan196
Route metric is 0, traffic share count is 1

#sh ip route 10.64.16.0
Routing entry for 10.64.16.0/23
Known via "eigrp 77", distance 90, metric 3072, precedence routine (0), type internal
Redistributing via eigrp 77
Last update from 10.254.1.2 on GigabitEthernet1/0/1, 7w0d ago
Routing Descriptor Blocks:
* 10.254.1.2, from 10.254.1.2, 7w0d ago, via GigabitEthernet1/0/1
Route metric is 3072, traffic share count is 1
Total delay is 20 microseconds, minimum bandwidth is 1000000 Kbit
Reliability 255/255, minimum MTU 1500 bytes
Loading 1/255, Hops 1

3850 in user location 2

EIGRP neighbors

H Address Interface Hold Uptime SRTT RTO Q Seq
(sec) (ms) Cnt Num
0 192.168.20.254 Gi1/0/12 14 12:09:54 1 100 0 2594 -> Nexus 93180-2 in DC 2
2 10.254.1.1 Gi2/0/12 13 2y20w 4 100 0 10266 -> 3850 in user location 1

Routing table

#sh ip route 10.65.196.0
Routing entry for 10.65.196.0/23
Known via "eigrp 77", distance 90, metric 3072, precedence routine (0), type internal
Redistributing via eigrp 77
Last update from 10.254.1.1 on GigabitEthernet2/0/12, 08:01:50 ago
Routing Descriptor Blocks:
* 10.254.1.1, from 10.254.1.1, 08:01:50 ago, via GigabitEthernet2/0/12
Route metric is 3072, traffic share count is 1
Total delay is 20 microseconds, minimum bandwidth is 1000000 Kbit
Reliability 255/255, minimum MTU 1500 bytes
Loading 1/255, Hops 1

#sh ip route 10.64.16.0
Routing entry for 10.64.16.0/23
Known via "connected", distance 0, metric 0 (connected, via interface)
Redistributing via eigrp 77
Routing Descriptor Blocks:
* directly connected, via Vlan16
Route metric is 0, traffic share count is 1

[balaji.bandi]

high level i do not see any issue (since you already change the topology to use different path we can identify what is the issue

since the routes are installed from DC1 side for Location 2

check some guide lines when you using vPC :

https://www.cisco.com/c/en/us/support/docs/ios-nx-os-software/nx-os-software/217274-understand-virtual-port-channel-vpc-en.html#toc-hId--2010709334

take note that the route is pointing to Nexus switches in DC1 as I had to increase delay on the interface towards 3850 switch on location 2 as the users where experiencing problems when traffic tried going to this network using directly attached link; quick fix to resolve user connectivity problems in user location 2

we are not sure what kind of user experience ? they don't have connectivity or they have intermittent connection or routing loops ?

[igor.hamzic81]

As for the user experience the main issue was that the network traffic from the user network in location 2 was very bad. A lot of time outs, web pages opening insanely slow if at all in some cases, when pinging resources connected to Nexuses there were timeouts, ...

Since it is now out of office hours I have now recreated the issue by removing delay on Nexus 2 in DC 2. These are the results of the routing tables on the equipment.

Nexus 93180-1 in DC 1

# sh ip route 10.65.196.0
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%<string>' in via output denotes VRF <string>

10.65.196.0/23, ubest/mbest: 1/0
*via 10.254.2.1, Vlan720, [90/3072], 18w4d, eigrp-Core_routing, internal

# sh ip route 10.64.16.0
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%<string>' in via output denotes VRF <string>

10.64.16.0/23, ubest/mbest: 2/0
*via 10.64.3.5, Vlan3, [90/3328], 00:01:16, eigrp-Core_routing, internal
*via 10.254.2.1, Vlan720, [90/3328], 1d11h, eigrp-Core_routing, internal

Nexus 93180-2 in DC 1

# sh ip route 10.65.196.0
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%<string>' in via output denotes VRF <string>

10.65.196.0/23, ubest/mbest: 1/0
*via 10.254.2.1, Vlan720, [90/3072], 18w4d, eigrp-Core_routing, internal

# sh ip route 10.64.16.0
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%<string>' in via output denotes VRF <string>

10.64.16.0/23, ubest/mbest: 2/0
*via 10.64.3.5, Vlan3, [90/3328], 00:03:44, eigrp-Core_routing, internal
*via 10.254.2.1, Vlan720, [90/3328], 1d11h, eigrp-Core_routing, internal

Nexus 93180-1 in DC 2

# sh ip route 10.65.196.0
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%<string>' in via output denotes VRF <string>

10.65.196.0/23, ubest/mbest: 2/0
*via 10.64.3.2, Vlan3, [90/3328], 18w4d, eigrp-Core_routing, internal
*via 10.64.3.3, Vlan3, [90/3328], 18w4d, eigrp-Core_routing, internal

# sh ip route 10.64.16.0
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%<string>' in via output denotes VRF <string>

10.64.16.0/23, ubest/mbest: 1/0
*via 10.64.3.5, Vlan3, [90/3328], 00:05:34, eigrp-Core_routing, internal

Nexus 93180-2 in DC 2

# sh ip route 10.65.196.0
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%<string>' in via output denotes VRF <string>

10.65.196.0/23, ubest/mbest: 3/0
*via 10.64.3.2, Vlan3, [90/3328], 18w4d, eigrp-Core_routing, internal
*via 10.64.3.3, Vlan3, [90/3328], 18w4d, eigrp-Core_routing, internal
*via 192.168.20.10, Eth1/31, [90/3328], 00:08:39, eigrp-Core_routing, internal

# sh ip route 10.64.16.0
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' denotes best mcast next-hop
'[x/y]' denotes [preference/metric]
'%<string>' in via output denotes VRF <string>

10.64.16.0/23, ubest/mbest: 1/0
*via 192.168.20.10, Eth1/31, [90/3072], 00:09:05, eigrp-Core_routing, internal

3850 in user location 1

#sh ip route 10.65.196.0
Routing entry for 10.65.196.0/23
Known via "connected", distance 0, metric 0 (connected, via interface)
Redistributing via eigrp 77
Routing Descriptor Blocks:
* directly connected, via Vlan196
Route metric is 0, traffic share count is 1

#sh ip route 10.64.16.0
Routing entry for 10.64.16.0/23
Known via "eigrp 77", distance 90, metric 3072, precedence routine (0), type internal
Redistributing via eigrp 77
Last update from 10.254.1.2 on GigabitEthernet1/0/1, 7w0d ago
Routing Descriptor Blocks:
* 10.254.1.2, from 10.254.1.2, 7w0d ago, via GigabitEthernet1/0/1
Route metric is 3072, traffic share count is 1
Total delay is 20 microseconds, minimum bandwidth is 1000000 Kbit
Reliability 255/255, minimum MTU 1500 bytes
Loading 1/255, Hops 1

3850 in user location 2

#sh ip route 10.65.196.0
Routing entry for 10.65.196.0/23
Known via "eigrp 77", distance 90, metric 3072, precedence routine (0), type internal
Redistributing via eigrp 77
Last update from 10.254.1.1 on GigabitEthernet2/0/12, 00:12:08 ago
Routing Descriptor Blocks:
* 10.254.1.1, from 10.254.1.1, 00:12:08 ago, via GigabitEthernet2/0/12
Route metric is 3072, traffic share count is 1
Total delay is 20 microseconds, minimum bandwidth is 1000000 Kbit
Reliability 255/255, minimum MTU 1500 bytes
Loading 1/255, Hops 1

#sh ip route 10.64.16.0
Routing entry for 10.64.16.0/23
Known via "connected", distance 0, metric 0 (connected, via interface)
Redistributing via eigrp 77
Routing Descriptor Blocks:
* directly connected, via Vlan16
Route metric is 0, traffic share count is 1

Everything looks as it should but the more I look at it the more it looks like a loop/glitch somewhere. I will do additional tests and try to figure this out.

If you have any additional insights please share them.