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Interfaces are down with Protocol down status. Why?

smart5
Level 1
Level 1

Hi All,

Need some advices on this issue. Yesterday we have a power maintenace activity which we shut down 2 of our core switches. When we power up these 2 swicthes, there's a problem i observed:

Out of the multiple interfaces which i created, some of them are up and running and some are remained down (Status n Protocol Down). This adnormalty is observed on our core switch 2, core switch 1 have all the interfaces up and running.

When i do a show standby bri on the SW2, those interfaces that are down are stuck in init status which is normal since the interfaces are down.

My questions here are:

1) Why are these interfaces remained down for quite a long time then it resolved by itself without doing anything?

2) What can be done to troubleshoot this issue to isolate the problem?

2 Replies 2

smart5
Level 1
Level 1

switches are running in Hybrid mode.

CatOS: cat6000-sup2cvk8.7-6-12.bin

MSFC IOS: c6msfc2-psv-mz.121-26.E2.bin

Abstract of the sh ip int bri on the CS2.

------------------------------------------

CS2#sh ip int bri

Interface IP-Address OK? Method Status Protocol

Vlan2 192.1.32.2 YES NVRAM up up

Vlan3 192.1.33.2 YES NVRAM DOWN DOWN

Vlan5 192.1.34.2 YES NVRAM DOWN DOWN

Vlan11 192.1.35.2 YES NVRAM up up

Vlan12 192.1.36.2 YES NVRAM up up

Vlan13 192.1.37.2 YES NVRAM DOWN DOWN

Vlan14 192.1.38.2 YES NVRAM DOWN DOWNp

Vlan15 192.1.238.2 YES NVRAM up up

Vlan105 192.1.47.6 YES NVRAM up up

Vlan305 192.1.47.6 YES NVRAM up up

Loopback0 192.1.47.5 YES NVRAM up up

Edison Ortiz
Hall of Fame
Hall of Fame

A SVI will remain down until a switchport that is member of that VLAN is up/up.

A SVI can also be up/up if you have an active trunk and the VLAN the SVI is part of, it's on forwarding state.

For the future, check all interfaces on SW2 for active ports on that VLAN and also check the if the trunk is forwarding that VLAN.

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