Ethernet Switches & Routers

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Posts: 1
Registered: ‎03-25-2016

Prefix announcement in virtual router RA messages?

[ Edited ]

Hello,

 

I'm using two ICX7450-48 with vrrp-e to have high availability in my network. They are running 08.0.30e software.

 

VRRP-E works fine with ipv4 but I'm having issues with ipv6 when trying to setup autoconfig for my clients. To make it short, the router announcement (ra) messages sent by the virtual router (vr) do not contain prefix information (2001:X:X:X/64) so my client cannot setup its global IPv6 address. Does anyone know how to fix this?

 

To make it a lot longer, both ICXs send ra messages with their own link-local address which act as gateway for the clients, and they also send ra messages from the vr. But some clients do not accept multiple gateways by default, other clients use a random gateway for each connection.... With vrrp-e, the clients need to have the vr as gateway. This is easy enough to do, as you can disable the ra messages from the router with the command

> ipv6 nd skip-interface-ra

 Thus, you're left with only the vr ra messages. This command was specifically designed for vrrp and vrrp-e. But these messages, unlike the router ra ones, do not contain any prefix information! I discovered this while sniffing the traffic. Their length is reduced from 118 bytes to 86. So new clients cannot setup their global IPv6 address.

 

One thing I noticed is that if the client receives both a vr ra message and a router ra message, he will always setup his global IP. But which gateway he will choose is seemingly random.

 

I tried many different scenarios but I have no failproof method of ensuring that the client is able to setup its global IP and gateway, AND that it still works if the routers switch between which is master and backup.

 

Do you know if there is an option so that the vr ra messages contain prefix information? Do you have another solution?

 

Thanks for your help!!

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