[c-nsp] Quick question on HSRP...

Gert Doering gert at greenie.muc.de
Wed Jan 1 06:38:54 EST 2014


Hi,

On Tue, Dec 31, 2013 at 07:54:10PM +0000, Phil Mayers wrote:
> On 31/12/2013 19:40, Gert Doering wrote:
> >On Tue, Dec 31, 2013 at 03:59:18PM +0000, Phil Mayers wrote:
> >>(Note that changing the HSRP version does not have this property; the
> >>old vMAC will be removed from the FDB, and the box won't forward traffic
> >>destined to it)
> >
> >Could someone remind me why I have to change HSRP to v2 to be able to
> 
> Not sure about that - maybe some fixed-size field in the HSRPv1 packet? 
> Been a while since I looked at it in a sniffer.

Having a different packet format for IPv6 makes sense, as, uh, it's not
IPv4 anyway :-) - but forcing me to move our IPv4 HSRP groups to v2 (which
incurs a reachability hit) to be able to enable *different* HSRP groups 
for IPv6 later on is just so slightly annoying.

[..]
> HSRP has a lot of weird edge cases on Cisco gear. IIRC a lot of them 
> relate to the size of the CPU MAC-address receive filter, and other 
> tedious crap that wouldn't matter if they moved off CPUs from last 
> millenium.

True.  Plus programmers that have never worked with a real network,
where things actually *evolve* over time...

[..]
> In fairness to Cisco, other vendors have blind spots. Juniper makes you 
> type a truly tedious amount of config to get VRRP working, though at 
> least commit scripts can automate that out of existence.

True, that one was done by someone who never had to do a router setup
as well, I bet.

gert

-- 
USENET is *not* the non-clickable part of WWW!
                                                           //www.muc.de/~gert/
Gert Doering - Munich, Germany                             gert at greenie.muc.de
fax: +49-89-35655025                        gert at net.informatik.tu-muenchen.de
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 305 bytes
Desc: not available
URL: <https://puck.nether.net/pipermail/cisco-nsp/attachments/20140101/38f63e8d/attachment.sig>


More information about the cisco-nsp mailing list