Is there any research out there that tries to estimate how long it will be
before BGP routers with 128M of RAM start to choke on the routing table? I
know there are a lot of factors - the number of BGP peers, how much "other
stuff" the router is doing, etc. - I'm really looking for a ballpark
estimate, if one exists.
I'm trying to convince someone NOT to use a Cisco 2650 for BGP
multihoming, and my argument will, IMO, be a bit more effective if
I can say "you'll need to replace it within X months/years"...
It looks like some recent aggregation has been helping to slow down the
growth. In any case, I've got 48MB (out of 128MB) free with 2 full views
and very little else (a few ACLs, OSPF) on a 7204VXR.
128M should do if you only have two or three upstreams, soft reconfiguration
disabled and almost nothing else enabled. Does anyone have experience with
zebra/mrt/... as a route server?. I need one and would like to you for the
cheap server based solution instead of having to buy a fully fledged router.
I'm trying to convince someone NOT to use a Cisco 2650 for BGP
> multihoming, and my argument will, IMO, be a bit more effective if
> I can say "you'll need to replace it within X months/years"...
You're doing the wrong thing. The 2650 can hold 8-10 full views
currently, and it's my guess that it will continue to be adequate for at
least 24 months. It costs about $3K. The alternative is a 7206VXR.
Let's posit that that would cost $30K and last for four years. The cost
of the 7206 is thus five times higher than simply buying appropriate
technology and upgrading as necessary. Plus if you upgrade over time, you
get to have new technology in the future, rather than being stuck with
what will seem like an old clunker for several years.
disabled and almost nothing else enabled. Does anyone have experience with
zebra/mrt/... as a route server?. I need one and would like to you for the
cheap server based solution instead of having to buy a fully fledged router.
I have used Zebra for about 2 years, with two and three uplinks
in what I would call a very basic conservative configuration
and good results. Currently using .89a
I was just recently trying to convince someone just the opposit. I lost
and they went with a non-Cisco solution.
If the 2650's 128mb of memory isn't enough, what are you recommending?
The only Cisco options I'm aware of are the 3660 series or 7x00
class...both of which are overkill for a small network with 2-3 T1's and
BGP peers.
Kinda a different twist on the topic, but I fail to see why a site of that
size needs to take a full table anyway. If all you have are a couple of
T1s multihomed to a couple of the larger networks, you can probably just
take customer routes and will achieve as optimum routing as possible. For
even better scaling and redundancy get two smaller routers (26xx or
rs3000) and run IBGP between them for still a more ecomical solution.
In most cases you don't. What pushed the client I'm thinking of to
multihome though was the C&W/PSI peering issue and the threat of similar
issues in the future. They only had connectivity to C&W and needed to
reach networks only on PSI. Multiple BGP peers and full routes would have
worked for them in this case. Customer routes and multiple defaults would
likely not have worked.
True.
Of course there are multiple ways to take customer routes, one of which is
filtering. A unique situation such as the CW/PSI mess would have called
for a prefix filter tweak, which, albeit, not automatic, relatively
painless on a small scale (i.e, you don't have to change hundreds of
customer routers because they don't have the talent themselves).
Then what happens when one of your two providers decides to cut off their
peering with another major provider? Do you just send half of your traffic
to that provider to nowhere? If you want fault tolerance against
connectivity losses, you need full routes.
to that provider to nowhere? If you want fault tolerance against
connectivity losses, you need full routes.
Not necessarily. You might get from your upstream their prefixes (or
anything you want) and point default to all with different metrics. So if
connectivity to one of your upstreams goes away, nothing breaks. Of course
if connectivity to an AS behind your default goes away you don't get backup
even if it were possible via some of the other upstreams.
peering with another major provider? Do you just send half of your traffic
to that provider to nowhere? If you want fault tolerance against
connectivity losses, you need full routes.
I tried partial... after changing which upstream provider was
my 'default route' a few times I quickly realized this was
stupid. Ram and CPU is cheap enough to make full routes,
even on a Cisco, a VERY desirable thing.
> peering with another major provider? Do you just send half of your
traffic
> to that provider to nowhere? If you want fault tolerance against
> connectivity losses, you need full routes.
I tried partial... after changing which upstream provider was
my 'default route' a few times I quickly realized this was
stupid. Ram and CPU is cheap enough to make full routes,
even on a Cisco, a VERY desirable thing.
Upgrading a 2650 to 128MB for USD 5,700 is not just cheap. The box itself is
around USD 3,300 ...
