MPLS support on 1800-series routers

Christoph sent me an interesting question a few days ago:

I played a bit arround with 2 Cisco 1803 and I found MPLS related configurations commands in IOS 12.4(15)T (Advanced Enterprise) on this box. MPLS was not listed as a included fearture in the Cisco Feature Navigator for this image and some searching at took me to a 2 year old document telling me that MPLS isn't supported on this series. Some more searching took me back to the Cisco Feature Navigator which lists MPLS as feature for the Cisco 1805 router (which uses the same IOS image, afaik).
So, I'm a bit confused now if MPLS is really working / supported on the low-end Cisco ISR 1800 fixed series?

MPLS was mostly available but never supported on low-end platforms (including Cisco 2600). In those days I've taken some heat for reusing existing 2600-based labs to teach Cisco-internal MPLS courses (since we were teaching the students to configure unsupported devices :).

Anyhow, the "not supported" means exactly that: it may be available (well, it is), it may work (it actually does), but if it's broken (and I've seen at least one low-end-platform-specific bug in the early days) you can't complain.

Is anyone aware whether the official support for the MPLS on 1800 series has changed? If so, please share your information with us.

If you need to offer a production-grade service to your customers, don't use unsupported equipment; if you need a solution for your personal needs or you're building a lab, go ahead.


  1. I can't go changing the configuration to verify it'll work, but it certainly looks like it would.

    No idea as to whether it's officially supported or not.

    bl-b203c-ar03# sh hardware | in Software
    Cisco IOS Software, C181X Software (C181X-ADVIPSERVICESK9-M), Version 12.4(6)T11, RELEASE SOFTWARE (fc2)
    bl-b203c-ar03# conf t
    bl-b203c-ar03(config)# mpls ?
    atm Configure ATM options
    ip Dynamic MPLS forwarding for IP
    label Label properties
    ldp Label Distribution Protocol
    static Configure static label bindings
    traffic-eng Configure Traffic Engineering parameters
  2. I read the doc (URL) sometime earlier this year on about MPLS Support on ISR Routers:

    "MPLS VPN and Multi-Virtual Route Forwarding Support for Cisco ISR"

    The minimum ISR platform that supports LER/LSR function is Cisco 1841. However, for the fixed configuration 1800 series neither LSR nor LER is supported according to this note. Like you have mentioned already, Ivan, the features may be available but would not be officially supported by Cisco. I have used Cisco 2600 series routers in the past to function as P and PE routers in my learning lab and I knew I would be on my own if something wasn't working :-)
  3. yeah on cisco 1841 we are using mpls but using as pre label switch router. While using as PE it creates lot of cef drops.
  4. Don't forget about MTU...
  5. Shivlu,

    You say you are using the 1841 as a pre-label switch router. Exactly what do you mean? Are you simply using VRF-Lite with no MPLS label switching configured?

    Also, you say you are seeing CEF drops. Exactly how? Are packets being dropped or punted to the processor?

    I am very curious because we are about to test and validate the 1841 as a MPLS access router operating as an LSR.

    Matt Woodling
  6. As of 12.4(20)T the fixed-config 1800 won't support MPLS functions anymore. That's in line with the whitepaper cited.

    12.4(15)T and rebuils may still 'work' but as noted - are unsupported.

    As for MTU - on modular ISRs 12.4(20)T and newer bring on MPLS MTU option for FE/GE interfaces.

    And don't always trust Feature Navigator - if in doubt, ask Your Cisco SE to get it black on white (or whatever).
  7. Which 2600 hardware platforms+specs and which IOS supported MPLS? Enquiring minds want to know!!
  8. This is my wild guess: 2610, Advanced Enterprise, 12.4. You might try booking some of our baseline MPLS remote labs; I'm pretty sure they still use the 2600-based rack.
  9. This comment has been removed by a blog administrator.
  10. Offically MPLS is supported on the 1841 platform and above....although the parser commands are found in fixed config routers, it is not offically supported.
Add comment