From: Reza Toghraee (reza@toghraee.com)
Date: Tue Oct 21 2008 - 16:53:15 ARST
Hi
The VLAN files in ISL header is 15 bits long, but I heard that only 10 bits
could be used and it can support VLANs from 1-1024.
But I just LAB it up.
R2(f0/0)-------(f0/2)_SW2_(f0/13)------ISL-TRUNK-------(f0/13)_SW1_(f0/1)---
---(f0/0)R1
R1 , R2 are in VLAN 3000
SW1
Rack1SW1(config)#do sh int trunk
Port Mode Encapsulation Status Native vlan
Fa0/13 desirable isl trunking 1
Port Vlans allowed on trunk
Fa0/13 1-4094
<<<<<<<<<<<<<<<<<=============================================
Port Vlans allowed and active in management domain
Fa0/13 1,3000
Port Vlans in spanning tree forwarding state and not pruned
Fa0/13 1,3000
Rack1SW1(config)#do show spann vlan 3000
VLAN3000
Spanning tree enabled protocol ieee
Root ID Priority 35768
Address 001a.2fd4.1980
Cost 19
Port 15 (FastEthernet0/13)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 35768 (priority 32768 sys-id-ext 3000)
Address 001a.2fd4.1d80
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- --------
--------------------------------
Fa0/1 Desg FWD 19 128.3 P2p
Fa0/13 Root FWD 19 128.15 Shr
Rack1SW1(config)#
And they can ping each other.
Reza
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Mahesh Shivaswamy
Sent: Tuesday, October 21, 2008 9:59 PM
To: Cisco certification
Subject: Extended VLAN & ISL trunking Lab 16 Sec 1.2
Hi,
In the above section the VLAN's have to be manually allowed on ISL trunks as
it would behave if VTP pruning was Enabled.
In solution guide, he has allowed VLAN 3003, on all trunks, My Q is :
1. Extended VLAN's are not allowed handled by ISL trunk, what is the use of
allowing them over all trunks links ?
2. How will ISL trunk process any frame in Extended VLAN range, will it drop
the frame ? or will it b/c over the trunk ?
rgds
Mahesh
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