11-24-2008 05:30 PM - edited 03-06-2019 02:39 AM
Network topology consists of 3 buildings(Two 6509 & 4500).
HSRP is running between the Core 6500 switches.
Existing topology is using native VLAN 1(10.1.1.0/24) for all dot1q trunks.
Plan is to introduce Layer 3 switching for the DATA and Voice VLAN with the 3 core switches configured as the default gateway.
Each core switch will have a unique DATA and VOICE VLAN for layer3 switching.
At the same time I can still use the Layer 2 VLANs (VLAN 1 & 100) on all switches in the campus
EIGRP protocol will run between all core switches.
A layer 2 and layer 3 link will be connected between all 3 Core switches (Diagram)
Please comment/advise on network. Will this solution be possible?
Solved! Go to Solution.
11-26-2008 12:04 AM
Hello Colm,
I suggest to manually configure the set of allowed Vlans on each trunk on a per link basis on the long term is better because VTP pruning doesn't stop STP frames so if you allow all vlans on all trunks the topology for each vlan can include links that can be excluded once for all by using the trunk allowed command.
You need the network command also for the "L2" subnets in case the local L3 switch misses its link to them it can reach via the other devices.
Hope to help
Giuseppe
11-25-2008 01:43 PM
Hello Colm,
I think you can do it.
However, usage of Vlan1 is not recommended for security reasons.
It could be a good idea to use a different Vlan for management purposes and leave vlan1 just for VTP or other L2 protocols.
That vlan can be campus wide as Vlan1.
For example in our campuses we usually use vlan100 for management.
Hope to help
Giuseppe
11-25-2008 04:20 PM
Hi Giuseppe,
Thanks for feedback. The customer existing network is using native VLAN1. This will need to be changed.
Regarding L2/L3 switching, will I need to apply vlan pruning on the dot1q trunks allowing VLAN 1 & 100 only over the l2 trunk links?
For the l3 switching, I have decided to use Eigrp protocol as all devices are Cisco. Do I need to add the L2 subnets under eigrp on all core switches (example below)
6509-A
router 250
network 10.0.0.0 ! L2 subnets
network 172.16.10.0 0.0.0.255
network 172.16.100.0 0.0.0.255
Regards,
Colm
11-26-2008 12:04 AM
Hello Colm,
I suggest to manually configure the set of allowed Vlans on each trunk on a per link basis on the long term is better because VTP pruning doesn't stop STP frames so if you allow all vlans on all trunks the topology for each vlan can include links that can be excluded once for all by using the trunk allowed command.
You need the network command also for the "L2" subnets in case the local L3 switch misses its link to them it can reach via the other devices.
Hope to help
Giuseppe
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