[j-nsp] MX104 capabilities question

Ross Halliday ross.halliday at wtccommunications.ca
Mon Jun 6 20:09:26 EDT 2016

We made the same move, from a network of SUP720-3CXLs up to MX104, over the last two years. Our busiest MX104 ingests 3 full feeds and around 100k prefixes via an IXP.

I'll echo Mark's sentiments: The MX104 has similar problems in that the CPU must update the FIB when the RIB changes. Small things like individual peers or normal churn aren't a big deal, but if we drop a major peer (say 300k prefixes destined to them), it's not pretty. It's not a slug like the 600 MHz MIPS SUP720 RP, but you can anticipate a couple minutes of reachability problems while the hardware shortcuts are updated to point out somewhere that accepts packets.

The MX104 is a great value box, but lacks some features which make it a "big boys" router. Aside from the RE, the control plane isn't as segregated as I thought, leading to interesting bugs like PR1031696 - which caused me to briefly lose all 10G optics in the entire chassis while installing an XFP; as well as some irritating behaviour from the ddos-protection mechanism. The larger chassis are *sort of* like running DFC cards in a 6500, were forwarding operations are pushed down. MX104 entirely relies on an integral system in the chassis and all you install are MICs, *sort of* like running a module with CFC and relying on the SUP.

I agree that you should spring for the MX240, which allows you the better RE, if you can afford/justify it. Unfortunately the larger MX platforms require the use of MPCs (not just MICs) so you wind up with a pretty awful number "just" to get a better RE, but there's a significant architectural difference, too. Depends on whether these are worth it to you or not. I imagine we'll eventually upgrade some of our key MX104s to the grown-up versions and reuse them elsewhere, but for now they do the job! 


> -----Original Message-----
> From: juniper-nsp [mailto:juniper-nsp-bounces at puck.nether.net] On Behalf
> Of Mark Tinka
> Sent: Monday, June 06, 2016 4:16 AM
> To: Ralph E. Whitmore, III
> Cc: juniper-nsp at puck.nether.net
> Subject: Re: [j-nsp] MX104 capabilities question
> On 6/Jun/16 10:01, Ralph E. Whitmore, III wrote:
> > I am in the process of replacing my old cisco650x hardware and was
> steered to this list to pose the following questions:
> >
> > I have 4 primary BGP transits  each delivering 600k+ routes to me and we
> will be adding another probably 600k+peer in the near future.  The sales
> rep recommended the MX 104 to us first, but then came back to us and said
> "Sorry this router isn't adequate for your needs you need to be in the
> MX240 Chassis" I read the spec's I can find and it says from a routing
> engine perspective (RE-S-MX104)  that it will handle the routes with room
> to grow on."
> >
> > >From Juniper:
> > IPv4 unicast FIB 1 million
> > IPv6 unicast FIB  512K
> >
> > Ipv4 RIB   4 million
> > IPv6 RIB  3 million
> >
> >
> > So the question is:  is there some other limiting factor(s)  that should
> steer me away from the MX104 to the MX240 Chassis? Is the sales rep
> blowing smoke?  I am hoping to find someone here who has tried this config
> and will either say yes this is great solution or  OMG, I'd never try that
> again.
> The MX104 will support 4x BGP sessions in the control plane (4GB RAM).
> The problem is that the CPU on this router is massively slow, so you
> will be in pain if you've got lots of churn.
> FIB-wise, you will be fine with the MX104.
> If you have the cash, go for the Intel-based RE's (MX240/480/960). If
> you don't mind Cisco, consider the ASR1000-X platforms.
> Mark.
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