CCNP TSHOOT 6.0 - Cisco Learning Home
CCNP TSHOOT 6.0 - Cisco Learning Home
CCNP TSHOOT 6.0 - Cisco Learning Home
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<strong>CCNP</strong>v6 <strong>TSHOOT</strong><br />
A VLAN interface or SVI is up if there is at least one interface in the spanning-tree forwarding state for that VLAN.<br />
This implies that if an SVI is down, you should verify VLAN existence, VLAN port assignments, and the spanningtree<br />
state for the SVI.<br />
In the output above, you can see that a missing VLAN results in a VLAN interface that is in state “down, line<br />
protocol is down.”<br />
Verify SVI Status (VLAN with No Port Assigned)<br />
DLS1#show vlan id 100<br />
VLAN Name Status Ports<br />
---- -------------------------------- --------- -------------------------------<br />
100 MGMT active<br />
VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2<br />
---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------<br />
100 enet 100100 1500 - - - - - 0 0<br />
DLS1#show interfaces vlan 100<br />
Vlan100 is up, line protocol is down<br />
Hardware is EtherSVI, address is 0017.5a5b.b441 (bia 0017.5a5b.b441)<br />
Internet address is 10.1.100.252/24<br />
<br />
When the VLAN exists but no ports are assigned to that VLAN, the status of the SVI changes to “up, line protocol<br />
is down.”<br />
Verify SVI Status (VLAN with No Port in Spanning-Tree Forwarding State)<br />
DLS1#show spanning-tree vlan 100<br />
<br />
Interface Role Sts Cost Prio.Nbr Type<br />
------------------- ---- --- --------- -------- --------------------------------<br />
Po1 Desg LRN 12 128.56 P2p<br />
Po10 Desg LRN 12 128.128 P2p<br />
DLS1#show interfaces vlan 100<br />
Vlan100 is up, line protocol is down<br />
Hardware is EtherSVI, address is 0017.5a5b.b441 (bia 0017.5a5b.b441)<br />
Internet address is 10.1.100.252/24<br />
<br />
Finally, if ports are assigned to the VLAN and at least one of these physical ports (trunk or access port) is up, one<br />
more condition needs to be met: The spanning-tree state for at least one of the ports needs to be forwarding.<br />
Under normal circumstances, if there is at least one interface assigned to a VLAN, an interface is in spanning-tree<br />
forwarding state. Either the switch is the root for the VLAN and all the ports assigned to the VLAN are designated<br />
ports and therefore forwarding, or the switch is not the root and it has a root port that is in forwarding state.<br />
As a result, when you are troubleshooting a multilayer switching problem and you find that the ingress interface is<br />
an SVI and it is down, there is an underlying Layer 2 problem for that VLAN and you need to initiate a Layer 2<br />
troubleshooting process.<br />
All contents are Copyright © 1992–2010 <strong>Cisco</strong> Systems, Inc. All rights reserved. This document is <strong>Cisco</strong> Public Information. Page 15 of 26
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