[sdnog] Hot standby routing protocol (HSRP)

[Daniel Shaw]

Hi Sara, SdNOG folk,

Although Nishal has already replied with pretty much all the info you need I'd just add my own experience also that using either of HSRP or VRRP are very simple and do work well. I've done both. Although, with VRRP I've also only tried it on Ciscos up to now.

But the warning I'd add is that while both pretty much "just work" on all the Cisco's I have access to (not that many actually, but a few), that is for IPv4.

When it comes to IPv6, I've run into a number of complications. HSRP and/or VRRP support for IPv6 is far more limited, and often non-existent on older IOS versions. Where I've used VRRP so far, that device just doesn't do it with IPv6 at all. And where I currently use HSRP, it supports IPv6, but there are tricks to the group numbers used, so you have to carefully plan the configuration, else you can't dual-stack the HSRP and just get an error about allocating a group or something. And, once you do get HSRP to work with IPv6 the "virtual" address can only be an FE80:: address, which can also complicate things if you have hosts on that client vlan that don't do IPv6 routing by RA, but rather have a static default gateway, because now that has to change.

In short - if you're running a dual-stack network, this might be quite a bit more complex than the IPv4 only examples you might come across.


-------- Original Message --------
Subject: [sdnog] Hot standby routing protocol (HSRP)
Local Time: January 5 2016 12:44 pm
UTC Time: January 5 2016 8:44 am
From: sara.alamin at sudren.edu.sd
To: sdnog at sdnog.sd

Hi All.
Happy New year , Wish you all the best :)
Today I was reading about interesting topic and it was new for me it is : HSRP.

What will happen if you lost your gateway?how can you access the internet ?Can you Configure your PC or your servers with multiple gateways? how can you provide a backup gateway for your customers?...

Hot standby routing protocol (HSRP) sets up a virtual IP address between two routers (could be more) to provide layer 3 fault tolerance for customers using a default gate way.

you can find more: https://www.ietf.org/rfc/rfc2281.txt

and here is a small video to show you the general concept:
https://www.youtube.com/watch?v=kxhdPI1jh6I


Enjoy!
--Sara Alamin--
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