Mikrotik BGP Question

Dennis Burgess dmburgess at linktechs.net
Mon May 24 16:44:54 UTC 2010

in V3 RouterOS's BGP support is very decent.  We typically don't have any issues with it!  :)  Whats nice is a router with 2 gig of RAM (cheap RAM too) can take multiple full table BGP feeds without issues.

Something else that's nice on our Dual Core systems is that while you are receiving the routes, you are only doing so on one core, instead of hitting high CPU while you receive all those, you only go up to 50% (on dual core system, and lower for quad and dual-quad systems).  So you don't have the huge CPU issue when you pull those routes. 

We had some upstream limit the BGP to something stupid like 128k!  Takes 50 min to get all the routes! 

Dennis Burgess, CCNA, Mikrotik Certified Trainer, MTCNA, MTCRE, MTCWE, MTCTCE, MTCUME 
Link Technologies, Inc -- Mikrotik & WISP Support Services
Office: 314-735-0270 Website: http://www.linktechs.net
LIVE On-Line Mikrotik Training - Author of "Learn RouterOS"

-----Original Message-----
From: Allan Eising [mailto:allan.eising+gmane at gmail.com] 
Sent: Monday, May 24, 2010 11:29 AM
To: nanog at nanog.org
Subject: Re: Mikrotik BGP Question

On Sun, 23 May 2010 08:21:47 +0200, Graham Beneke wrote:

> On 2010/05/21 11:56 PM, Martin List-Petersen wrote:
>> - Mikrotik still has some memory leaks in the BGP stack somewhere,
>> causing funny issues at times.
>> - Filters aren't adequate for my use, and lacking a lot on IPv4, but
>> even more on IPv4.
> I haven't seen either of those issues running the v4.x stream of
> RouterOS. The memory leak was solved a while ago and Mikrotik has fairly
> short release cycles.
> We have extensive inbound and outbound filters on our eBGP doing most of
> the normal things that you would do on a cisco. The IPv6 filters must be
> built via the terminal to avoid limitations with the current GUI but
> they also work very well

In some ways, I find the MikroTik RouterOS routing filter syntax a little 
more powerful than Cisco's route-maps. As routing filters work the same 
way as firewall filters, you can group rules in "chains" and reuse parts 
of your filters in other filters by jumping to another chain. This could 
be used, for instance, on a peering setup, where you have a number of 
rules per peer but also some common filtering for all peers, or to handle 
specific and generic filtering for your customers.

I haven't yet found anything that I missed being able to with filters, at 
least with BGP. With other routing protocols, it's another story.


Allan Eising

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