Solved: Re: SVI interface is up up despite all ports in vlan are down

mahesh18 · ‎03-10-2011

hi all,

As per Cisco book SVI interface is up when one layer 2 port in that vlan is in spanning tree forwarding mode.

Or

At leat one Layer 2 --access or trunk port exists on the switch and has link in the up state on this vlan.

I tested this on 2950 switch and unplug the cable from trunk ports

Now it shows all ports as down down

2950T#sh ip int brief
Interface IP-Address OK? Method Status Prot
ocol
Vlan1 unassigned YES TFTP administratively down down

Vlan10 192.168.10.5 YES NVRAM up up

FastEthernet0/1 unassigned YES unset administratively down down

FastEthernet0/2 unassigned YES unset administratively down down

FastEthernet0/3 unassigned YES unset down down

FastEthernet0/4 unassigned YES unset down down

FastEthernet0/5 unassigned YES unset down down

FastEthernet0/6 unassigned YES unset down down

FastEthernet0/7 unassigned YES unset administratively down down

FastEthernet0/8 unassigned YES unset down down

FastEthernet0/9 unassigned YES unset administratively down down

FastEthernet0/10 unassigned YES unset down down

FastEthernet0/11 unassigned YES unset administratively down down

FastEthernet0/12 unassigned YES unset administratively down down

FastEthernet0/13 unassigned YES unset administratively down down

FastEthernet0/14 unassigned YES unset administratively down down

FastEthernet0/15 unassigned YES unset administratively down down

FastEthernet0/16 unassigned YES unset administratively down down

FastEthernet0/17 unassigned YES unset administratively down down

FastEthernet0/18 unassigned YES unset administratively down down

FastEthernet0/19 unassigned YES unset down down

FastEthernet0/20 unassigned YES unset down down

FastEthernet0/21 unassigned YES unset down down

FastEthernet0/22 unassigned YES unset administratively down down

FastEthernet0/23 unassigned YES unset administratively down down

FastEthernet0/24 unassigned YES unset administratively down down

GigabitEthernet0/1 unassigned YES unset administratively down down

GigabitEthernet0/2 unassigned YES unset administratively down down

2950T#

But vlan 10 is still sown as up up.

2950T#sh int vlan 10
Vlan10 is up, line protocol is up
Hardware is CPU Interface, address is 000b.bece.bbc0 (bia 000b.bece.bbc0)
Internet address is 192.168.10.5/24
MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
     reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:07:17, output never, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
     17302372 packets input, 1231695770 bytes, 0 no buffer
     Received 7780 broadcasts (0 IP multicast)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 1 ignored
     11805029 packets output, 1047960802 bytes, 0 underruns
     0 output errors, 2 interface resets
     0 output buffer failures, 0 output buffers swapped out
2950T# sh run int vlan 10
Building configuration...

Current configuration : 82 bytes
!
interface Vlan10
ip address 192.168.10.5 255.255.255.0
no ip route-cache
end

Can someone please expalin me why this vlan is up a up ??

Thanks

mahesh

ranraju · ‎03-10-2011

Can you post the outputs for "show vlan id 10", "show int trunk" of the switch

View solution in original post

glen.grant · ‎03-10-2011

For some reason it thinks that trunk is up thus why the SVI is still up . If everything shut then reload it and see if it clears...

View solution in original post

ranraju · ‎03-10-2011

HI Mahesh,

If you can reproduce this issue on your switch, you should open up a TAC case, as this is a buggy behavior.

And next time, before reloading - flap the vlan, do a shut/no shut on the SVI and check if it goes back to up/down state.

Regards,

ranraju

View solution in original post

ranraju · ‎03-10-2011

Can you post the outputs for "show vlan id 10", "show int trunk" of the switch

mahesh18 · ‎03-10-2011

Hi,

thanks for reply.

here is info

2950T#sh vlan id 10

VLAN Name                             Status    Ports
---- -------------------------------- --------- -------------------------------
10   VLAN0010                         active    Fa0/3, Fa0/10, Fa0/18, Fa0/19
                                                Fa0/21

VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2
---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------
10 enet 100010 1500 - - - - - 0 0

Remote SPAN VLAN
----------------
Disabled

Primary Secondary Type Ports
------- --------- ----------------- ------------------------------------------

2950T#sh int trunk

Port Mode Encapsulation Status Native vlan
Fa0/20 on 802.1q trunking 1

Port Vlans allowed on trunk
Fa0/20 none

Port Vlans allowed and active in management domain
Fa0/20 none

Port Vlans in spanning tree forwarding state and not pruned
Fa0/20 none
2950T#

glen.grant · ‎03-10-2011

For some reason it thinks that trunk is up thus why the SVI is still up . If everything shut then reload it and see if it clears...

mahesh18 · ‎03-10-2011

Hi glen,

I did reload .

Now it shows status as up and down

here is output

2950T#sh int vlan 10
Vlan10 is up, line protocol is down*********************
Hardware is CPU Interface, address is 000b.bece.bbc0 (bia 000b.bece.bbc0)
Internet address is 192.168.10.5/24
MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,
     reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output never, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
     0 packets input, 0 bytes, 0 no buffer
     Received 0 broadcasts (0 IP multicast)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 packets output, 0 bytes, 0 underruns
     0 output errors, 2 interface resets
     0 output buffer failures, 0 output buffers swapped out

2950T#sh ver
Cisco Internetwork Operating System Software
IOS (tm) C2950 Software (C2950-I6K2L2Q4-M), Version 12.1(22)EA13, RELEASE SOFTWA
RE (fc2)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2009 by cisco Systems, Inc.
Compiled Fri 27-Feb-09 22:20 by amvarma
Image text-base: 0x80010000, data-base: 0x80680000

ROM: Bootstrap program is C2950 boot loader

2950T uptime is 1 minute
System returned to ROM by power-on
System image file is "flash:c2950-i6k2l2q4-mz.121-22.EA13.bin"

This product contains cryptographic features and is subject to United
States and local country laws governing import, export, transfer and
use. Delivery of Cisco cryptographic products does not imply
third-party authority to import, export, distribute or use encryption.
Importers, exporters, distributors and users are responsible for
compliance with U.S. and local country laws. By using this product you
agree to comply with applicable laws and regulations. If you are unable
to comply with U.S. and local laws, return this product immediately.
--More--

mahesh18 · ‎03-10-2011

Hi Glen and Ranraju,

Many thanks for you help on this.

Regards

mahesh

ranraju · ‎03-10-2011

HI Mahesh,

If you can reproduce this issue on your switch, you should open up a TAC case, as this is a buggy behavior.

And next time, before reloading - flap the vlan, do a shut/no shut on the SVI and check if it goes back to up/down state.

Regards,

ranraju

mahesh18 · ‎03-10-2011

Hi Ranraju,

Many thanks again.

mahesh