BGP Router

digitmc · 6th August 2008

Hi,

What is the current size of the Global Routing Table and what is the minimum amount of memory required in a router to have 2 full transit providers and take partial routes from one IXP?

We have Cisco 7204VXR chassis and checking on the routing processor to use, initially there will not be a huge volume of traffic and our budget is small to start with, so what would be a suitable routing processor go for? NPE-225, NPE-400 or all the way to the NPE-G1? Would 256MB be suitable for this? Or would you have to go up to 512MB / 1GB?

Is the only limitation on the number of routes the amount of memory or are there any other restrictions that will have a hard limit on the number of routes allowed?

Thanks for you help

administrator · 6th August 2008

You could save on memory by taking default routes or really cut down routes from the global providers and then your partial routes.

But im a bit out of the loop these days on routing tables :P

Karl · 6th August 2008

We're seeing roughly 258k routes from our full tables. With Cisco, I'd imagine you're going to have to have 512MB to cope with that on the VXR (although it's been a long long long time since I ever looked at a VXR).

No idea what prices VXR NPEs go for these days, but it could be just as cheap to get something like a J-4350/6350

Schumie · 6th August 2008

Cisco world, you would be at a push with 256MB of memory (you'd be looking at a real tight IOS version with teh full table).

You could perform your own filtering to make sure you don't use too much memory, but for the hassle and effort it's probably just as easy to get an NPE-400 with 512MB.

If you have the need for the throughput ability for the NPE-G1/G2, theirs no point doing anything other than 1GB really. The G2 comes with this as standard and can be increased to 2 if needed (not that I see that need for quite a while!)

Maybe if you specify your throughput needs as well as circuit type we might be able to help you specify something a little more accurately?

digitmc · 6th August 2008

Throughput isn't really an issue, but latency is. It will be running on fast ethernet ports to the upstream providers, so 100MBit will be the initial maximum port speed.

Could I take a full routing table from one transit provider, don't filter anything from the IXP and then just take a default from the other transit provider (which would only be preferred when the primary transit provider goes down and there is no available route over the IXP)?

I assume that would reduce the stress on the routing tables and therefore the memory requirements.

Latency is the most important part of this application. Would the engines make a difference to latency? or just throughput? Ie. comparing the NPE-225 and NPE-G2, obviously the throughput on the G2 is going to be huge, but will this affect the latency of the connection (assuming the throughput of our network will be relatively low anyway?)

I basically want to set this up in a way that is cheap for our needs, but gives us complete control over routing, low latency to our peers and allows a future pathway for expansion.

danfoster · 6th August 2008

Surely if you're going to do that you might as well just take two default routes from the transit providers, preference the IXP the highest, the primary transit next and then the backup transit lowest. That way the only routes you'll have in your table are the ones from the IXP, and they'll always win if present as they'll be more specific than the default routes.

Karl · 6th August 2008

If you want cheap, then setup your own router with Quagga or OpenBGPD - you don't get much cheaper then that, and it'll happily do 300Mbit/s+ and take as many full tables as your CPU (for convergence and inserting the routes) and memory can cope with.

danfoster · 6th August 2008

Yep I'll second the quagga route; cisco for the sake of the name is a pointless persuit, especially at the lower level.

othellotech · 7th August 2008

Quote:

Originally Posted by digitmc

What is the current size of the Global Routing Table

~260,000 routes

Quote:

Originally Posted by digitmc

and what is the minimum amount of memory required in a router to have 2 full transit providers and take partial routes from one IXP?

you'll get one full feed on 256Mb
2 feeds and 1 peering will need 512 now, the more *sessions* you add the more memory you'll need.

Quote:

Originally Posted by digitmc

Is the only limitation on the number of routes the amount of memory or are there any other restrictions that will have a hard limit on the number of routes allowed?

Memory is just one of the restrictions, but certainly the one most people hit first, followed by the number of sessions - which is ok if you get routes through an MLP and an issue if you have to setup a session with each IXP member

JamesC · 7th August 2008

If he's looking at latency as the only consideration - I've seen it on more than one occassion (not to suggest it's the norm) where routing to a destination prefix is actually higher latency over an IXP than over transit as the transit would be e.g. us > NTT > Them whereas the IXP is us > someone > someone > them and so the IXP route is 2-3ms longer, obviously it's not too much of an issue, as if you're seeing a bizarre path to an ASN you just depreference that ASN over the IXP to below your transit preference

markcastle · 7th August 2008

Personally I think if I was to start again I'd try to leapfrog the quagga route and head straight for a couple of Junipers. Pref M series of course, but J series can be a great starting point... Load the RAM up with 2GB from Crucial. Some great deals can be had if you know the right questions to ask. Don't get me wrong, Quagga served us well and still does in some remote parts of our network, but i'd take the flexibility and power of JUNOS over it anyday.

CrystalVPS · 7th August 2008

We're *very* happy with our 2 J6350s - had to do a CF upgrade to get them to 9.1 though given ours only came with 128MB CFs - easy enough to do though

gateways on Layer 3 Cisco switches with iBGP to the Junipers - reliability has been flawless in the year we've been on this setup.

alexcf · 7th August 2008

I second Mark on the Juniper route. If you want to build a serious network, I would go down the route of a "named" vendor in the market, rather than a Quagga...

Now, before I get rants and "what do you mean my networks not serious because I use Quagga" type comments; I would just like to remind those people that if you go with a "named" vendor, you can buy software/hardware support which will mean IF you have a problem, then you have access to the right people to fix it.

On the other hand, if you've used Cisco before, you will find Juniper a bit of a culture shock, so Quagga is a more sensible option if you don't have time to learn it. You will also find a lot more on Google about how to do certain parts of the configuration compared to Juniper.

Having Juniper in your network does kind of give you a little bit of a "pro-ness" about you, it's just a status thing... I'm sure DanG will agree

.

At the end of the day, we as a whole still manage and roll out more Ciscos than Junis, but if I look back at the last few months, I've done more installations of J-series than I have Cisco.

Feel free to send me a PM if you've got any further questions which aren't suitable for public consumption.

samb · 7th August 2008

Quote:

Originally Posted by alexcf

Now, before I get rants and "what do you mean my networks not serious because I use Quagga" type comments; I would just like to remind those people that if you go with a "named" vendor, you can buy software/hardware support which will mean IF you have a problem, then you have access to the right people to fix it.

Or you can go down the Quagga route and get access to someone like us to support it if you have a problem.

As always, there's more than one way to achieve the same result..

goscombtech · 8th August 2008

Quote:

Originally Posted by alexcf

Having Juniper in your network does kind of give you a little bit of a "pro-ness" about you, it's just a status thing... I'm sure DanG will agree

.

We don't have many Junipers... I also don't have one as my home DSL router!

where's the sarcasm smiley!?