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VLAN IP (Failover).

Karl Collinson
Frequent Advisor

VLAN IP (Failover).

Afternoon\Morning All,

1x Core
8x Edge switches.
2x VLAN (Default VLAN & VoIP VLAN)
MSTP enabled

All switches have Default VLAN IP for Management.
1 IP for VoIP VLAN on Core, VoIP VLAN tagged on all uplinks to edges.

What would happen to the LAN if the core failed removing the IP for VoIP VLAN and resulting in MSTP rerouting traffic down the redundant edge uplinks?

Would i only lose VLAN management for the VoIP VLAN and QoS? Or worse?


Picture Enclosed.
cenk sasmaztin
Honored Contributor

Re: VLAN IP (Failover).

hi karl
my advice you can use two core switch and you make vrrp and mst config on your network

each edge switch connect two another uplink ports core switches


Karl Collinson
Frequent Advisor

Re: VLAN IP (Failover).

Alright Cenk!!! ;-)

Got a diagram to go with your recommendation?

Done the HP Edge adaptive course now but never touched on the above recommendation.

Thx m8,
Igor Ybema

Re: VLAN IP (Failover).

As I understand you are not using the switches as routers. The extra IP-address on the VOIP vlan is only for management also in this case. So you can even delete these addresses.

VRRP is only needed if you use the core as router.

In your case, if the core fails, MSTP will open the redundant paths if available so traffic will continue to each edge switch. I presume you do have these redundant paths already between the edge switches.
Pieter 't Hart
Honored Contributor

Re: VLAN IP (Failover).

in your current config you only have a single core-switch. You use two edge switches on floor-4 for backup if the core switch fails.
in case op core-failure you may have traffic from edge7 through edge4a, edge4b to edge1.
Technically it will work, but it's a step-back as from edge1-core-edge7
(from single star-topology to two connected stars)
Cenk advises to double the coreswitch and connect all edge-switches to core1 and core2. (instead of core1 and edge4a or so).

Whats the need for a core-IP on the voip-vlan?
You have a separate managment vlan with seperate Ip's so yo can use it to manage all switches and other devices that are connected to this vlan.
if the core switch fails only the services delivered by this switch are unavailable.
so whats active on the core ?
routing ? QoS tagging? other VLAN's?

QoS is neccessary when multiple data streams are present in your network.
if the VoIP vlan and the management vlan are the only vlan used, what's the worry about QoS.
Karl Collinson
Frequent Advisor

Re: VLAN IP (Failover).

Morning All,
Some great points of interest there!

The 2 Edge switches are on floor 4 due to the amount of IP handsets.

Was going down the route of 802.1p\DSCP on the VoIP VLAN in case the customer @ a later time uses the Switches for more than just VoIP traffic.

The PBX (Mitel\Inter-tel Switch) is going to be plugged into to the Core.

The whole design aspect is in case the core fails the customer can just change the Interface the Mitel is interfaced with (as it happens more than 1 switch is required on floor 4).

No layer 3 routing, only VLAN and Tagging.

Look forward to your inputs,
Many Thanks =0)