11-20-2023 08:25 AM
Hello,
We have receved 2 configured new Nexus 93180YC-fx3.
CORE01: Link OSPF on ETH1/1 (Connected and OK)
CORE01 and CORE02 VPC activate.(L3 option activate)
VLAN 253 with HSRP configured.
When a Linux serveur traceroute and connected to Core01:
1 10.24.253.2 (10.24.253.2) 0.389 ms 0.367 ms 0.411 ms
2 10.24.254.4 (10.24.254.4) 0.392 ms 0.337 ms 0.314 ms
3 10.10.32.145 (10.10.32.145) 2.674 ms 2.739 ms 2.663 ms
When connected on the core02:
1 10.24.253.2 (10.24.253.2) 0.849 ms 0.826 ms 0.826 ms
2 10.24.253.2 (10.24.253.2) 0.362 ms 0.406 ms 0.447 ms
3 10.24.254.4 (10.24.254.4) 0.407 ms 0.344 ms 0.286 ms
4 10.10.32.145 (10.10.32.145) 2.626 ms 3.283 ms 3.294 ms
What can explain this double identical Hops ?
Bad configuration or normal due to HSRP and VPC ?
-------
Primary HSRP:
interface Vlan253
no shutdown
no ip redirects
ip address 10.24.253.2/24
no ipv6 redirects
ip router ospf 2 area 0.0.0.0
hsrp 53
ip 10.24.253.1
--------
11-24-2023 01:30 PM
Can you more elaborate about your issue
11-28-2023 02:31 AM
11-28-2023 02:35 AM
Thanks for your answer.
As show in the picture.
When server Connected to Core02
1 10.24.253.2 (10.24.253.2) 0.849 ms 0.826 ms 0.826 ms
2 10.24.253.2 (10.24.253.2) 0.362 ms 0.406 ms 0.447 ms
3 10.24.254.4 (10.24.254.4) 0.407 ms 0.344 ms 0.286 ms
4 10.10.32.145 (10.10.32.145) 2.626 ms 3.283 ms 3.294 ms
We can see 2 time: 10.24.253.2
And when i make test, The server say that identify Asym Trafic.
But not when connected on the first.
1 10.24.253.2 (10.24.253.2) 0.389 ms 0.367 ms 0.411 ms
2 10.24.254.4 (10.24.254.4) 0.392 ms 0.337 ms 0.314 ms
3 10.10.32.145 (10.10.32.145) 2.674 ms 2.739 ms 2.663 ms
I know that HSRP work in actif/actif on VPC but that provocate this Asym error ?
Thanks
11-28-2023 12:18 PM
This is traceroute
Server to nsk-1 ( hsrp vip is use by both nsk since it active/active)
1 10.24.253.2 (10.24.253.2) 0.849 ms 0.826 ms 0.826 ms
Here
Server to nsk1 to nsk2
Again since it vpc hsrp active/active
2 10.24.253.2 (10.24.253.2) 0.362 ms 0.406 ms 0.447 ms
Here
Server to nsk1 to nsk2 to core SW
3 10.24.254.4 (10.24.254.4) 0.407 ms 0.344 ms 0.286 ms
Here the end point
4 10.10.32.145 (10.10.32.145) 2.626 ms 3.283 ms 3.294 ms
So this normal behavior of vpc nsk I think.
I will check how we can remove the nsk2 from path.
MHM
11-28-2023 12:46 PM
Since it Single leg trt use vlan SVI of nsk1 as gw of server and check.
Note:- nsk1 is nsk server direct connect to it
MHM
11-29-2023 12:13 AM
Hello,
Thanks for your answer.
Test Make:
Remove interface vlan config from Nexus 2 but server always connected on it:
1 10.24.253.2 (10.24.253.2) 0.389 ms 0.367 ms 0.411 ms
2 10.24.254.4 (10.24.254.4) 0.392 ms 0.337 ms 0.314 ms
3 10.10.32.145 (10.10.32.145) 2.674 ms 2.739 ms 2.663 ms
Nexus 1 as Gateway :
1 10.24.253.2 (10.24.253.2) 0.289 ms 0.267 ms 0.311 ms
2 10.24.254.4 (10.24.254.4) 0.292 ms 0.335 ms 0.311 ms
3 10.10.32.145 (10.10.32.145) 2.401 ms 2.712ms 2.200 ms
Roll back: Interface Vlan back + HSRP + server on Nexus2
1 10.24.253.2 (10.24.253.2) 0.849 ms 0.826 ms 0.826 ms
2 10.24.253.2 (10.24.253.2) 0.362 ms 0.406 ms 0.447 ms
3 10.24.254.4 (10.24.254.4) 0.407 ms 0.344 ms 0.286 ms
4 10.10.32.145 (10.10.32.145) 2.626 ms 3.283 ms 3.294 ms
Asymm detection:
11-30-2023 09:11 AM
Server is connect via one leg to nsk vpc pair.
So if we use hsrp vip both nsk can forward traffic destiantion to this IP.
But this IP also use for reaching external subnet connect to nsk-2 that why the IP appear twice.
What I suggest is making server (since it single leg connect) use vlan svi of nsk-1 as gw
This make tracroute not show same IP twice.
MHM
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