8

A VLAN I need to use is allocated for internal usage (as per vlan internal allocation policy ascending). I can't (easily) move the traffic over to another VLAN for various practical reasons.

I was therefore wondering if there's a trivial way to re-allocate the internally reserved VLAN, without rebooting a PE node?

Output:

router(config)#int Te1/2.1070
router(config-subif)#encapsulation dot1q 1070
Command rejected: VLAN 1070 not available
(..)
router#show vlan internal usage | i ^1070
1070 vrf_50_vlan

(This is on a 7604 with ADVIPSERVICESK9-M v 12.2(33)SRE2)

13

You can remove the VRF temporarily:

sh ip vrf detail | i Id

Only reason this VLAN is even created is because either your VPN-CAM is turned off or you have more than 512 VRFs. If you don't have 512 VRFs, you can free up this internal VLAN without removing VRF by making sure VPN-CAM is activated. This may not be the simplest task as there are various reasons which mean VPN-CAM is disabled, most common reasons are:

  • You use 'class-default' in QoS, match 'any any' ACL instead
  • You use egress ACL in VRF, remove them

Once there are no reason to disable VPN-CAM, it gets renabled, and those VRF VLANs will disappear. This will also double your VRF performance, as you won't need to recirculate the packet in the PFC.

Without VPN-CAM your first PFC lookup will resolve VRF, second will resolve egress rewrite. With VPN-CAM before packet even hits PFC, VPN-CAM has already told you which table to look against, so PFC will directly return egress rewrite on single lookup.

To confirm if VPN-CAM is used or not, you can issue this command:

remote command switch sh mls vpn-cam 0 511

Long term, maybe change the allocation order, to order from 4k downwards, instead of 1k upwards.

  • First thing Monday, I'll look into if I can pull down those specific VRFs for the duration, thanks! I'm further going to look into your suggestions for longer term avoidance of the problems. – Jan May 24 '13 at 21:23
1

Only way I know of is to "shutdown" the port using the VLANID, create your vlan and then "no shutdown" the port. What is "vrf_50_vlan" assigned to?

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