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IGMP problems following changes

Tony Barrett_2
Frequent Advisor

IGMP problems following changes

I used to run my network in the single (default) VLAN, consisting of ProCurve 5406 (core), 5308's, 2800's and 2600's. An IP was allocated to each switch in vlan 1, the core was IGMP querier, and everything worked fine.

I've recently changed the config so the primary-vlan (1) is where the network clients reside, but I've created a new management-vlan (200) for all network management traffic. The IP for the primary-vlan has now moved to the management-vlan on each switch, so the primary-vlan currently has no IP assigned. The core switch is not routing.

Problem is, IGMP no longer seems to work. In the primary-vlan, igmp is still configured, but because no IP is assigned, nothing is updated. All other switches in the primary-vlan can no longer find a querier. You can't setup IGMP in the management-vlan, because the switches won't let you (by design). The manual implies you can still run IGMP in a vlan with no ip address (with some limitations), but it's not obvious how you make this work.

The core switch has the following assigned in vlan 1;

ip igmp
ip igmp querier

All other switches in vlan 1 are configured as;

ip igmp
no ip igmp querier

All switches have the following assigned;

primary-vlan 1
management-vlan 200

What is the best (simplest) way of getting this to work again?
Trusted Contributor

Re: IGMP problems following changes

Hi Tony.

The way I understand it is that VLAN 1 (Primary VLAN) does not have an IP on any of your switches right?

In order to become IGMP Querier however and IP Address must reside somewhere in VLAN 1. The limitation you were referring to (The manual implies you can still run IGMP in a vlan with no ip address (with some limitations)) just boils down to this as without an IP Address there can be no Querier. Remember IGMP uses a TTL=1 so you need an IGMP Querier PER VLAN.
ProCurve Networking Engineer
Pieter 't Hart
Honored Contributor

Re: IGMP problems following changes

advises are to leave vlan-1 as it is (primary) and move all endponts (clients/servers) out of vlan-1 to a new vlan, you tried the opposite?

look in the doc's on terms
"default vlan" : vlan exists on switch from factory + every ports is member of the default vlan).
and "primary vlan" : vlan used for switch-to-switch communication (like oldfashioned STP and CDP packets).
From factory both are mapped to vlan-1, but they are different things.

And there is "management vlan" : vlan dedicated to get access to a switch for management purposes. A management vlan is NOT routed to other subnets (so you allready say by design the switches won't let you configure this).

My first suggestion is to put the ip-adresses on vlan-1 back and assign a new management ip-address on vlan-200

You may also consider to configure vlan-200 as primary vlan.
This vlan then, is not only for access to the switch from a management station, but also for network-housekeeping and routing information.
You must remove the setting "management vlan" from vlan200 to configure it as "primary vlan".