Do you use CLNS in your network?

A few years ago, we've seen a lot of requests to design CLNS networks (primarily for network management purposes). I haven't heard about CLNS recently, so I'm wondering: is it still used or did it go the way X.25 did? You can help us all understand what's going on by responding to the quick poll I've set up: just open any page in my blog, select the answer from the poll in the top-right corner of the page and click Vote (the button might be labeled in your local language).

More detailed observations are also most welcome: just add a comment to this post.

9 comments:

  1. Used for ISIS, nothing outside of that. As ISIS is a core routing protocol in my current position and the last I seem to be the only one saying heavy in your poll... ;)

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  2. And if I learn today CLNS it's only for the sake of IS-IS and it's features!!!! :)

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  3. You probably should clarify that you are talking about routing CLNS/CLNP packets, not using CLNS as the underpinnings for IS-IS in an IP network.

    The only people I've ever talked to who used large CLNS networks in the 21st century are those who were using them for managing large SONET control networks. My understanding is that these can be quite vast, so it seems unlikely that they have disappeared entirely. But it's probably a specialized enough application that not many people are going to know about it.

    The last RFC I can find on CLNS is RFC 3147, dated 2001. There's also an expired draft of a CLNS/MPLS-VPN extension dated 2005. See http://tools.ietf.org/draft/draft-vohra-l3vpn-bgp-clns/draft-vohra-l3vpn-bgp-clns-00.txt

    So there definitely doesn't seem to be much contemporary activity on it.

    I'd be interested to see any additional followup you get on this topic.

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  4. Along with js's post, it seems as if most of the equipment vendors have added support for TL1 over IP. While there's undoubtedly some massive networks still running CLNS, this probably explains the drop-off in requests for new implementations.

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  5. I think that CLNS is probably a future technology. IPv6 looks a lot like next generation IPX (that never went anywhere) so I wonder if CLNS will be the sequel to IPV6. Old technology never dies, it just waits for a another time.

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  6. I think that CLNS is probably a future technology. IPv6 looks a lot like next generation IPX (that never went anywhere) so I wonder if CLNS will be the sequel to IPV6. Old technology never dies, it just waits for a another time.

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  7. CLNS still continues to be used in the telco DCN network for management of SONET/SDH boxes that still can be managed by CLNS / NSAP addressing.

    Its going to be there till I believe the SDH boxes die away slowly as newer SDH boxes will come with IP support for management.

    I have used IS-IS for routing CLNS and found MP-BGP support for MPLS in cisco boxes which has made things simpler . But the IOS codes are quite buggy .

    Interesting to see how OSI / CLNS implementation will be supported by MPLS VPN !!

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  8. I use isis L1 for local transport, L2 for man and mbgp for core routing, works like a wonder. Have about 15.000 NE distributed over ~25 countries.
    hosts with dual-protocol have integrated ip-addresses like 39.xxxx.xxxx.xxxx..1921.6823.0005.00 for 192.168.23.5.
    Also use Resource-record type NSAP in DNS

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  9. I run a Telco network with some 3,500 pure CLNS nodes in it. The CLNS protocol is solid once up and running.

    Compared to IPv4 addresses the OSI addresses are large and cumbersome but start to look like IPv6 more and more.

    There are different issues to deal with CLNS i.e. the DG is the closest until it fails, Cisco supports a CLNS version that acts subtly different to the IP/CLNS version (Integrated ISIS), very few people understand and can use it. Saying that we have it running so solidly you'd think it was perfect.

    I like it but feel, as JS above, that it will fade away in the Telco market as the IP managed devices take over but will live in the SP arena for the foreseeable future due to it's stability and multiple configuration options.

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Ivan Pepelnjak, CCIE#1354, is the chief technology advisor for NIL Data Communications. He has been designing and implementing large-scale data communications networks as well as teaching and writing books about advanced technologies since 1990. See his full profile, contact him or follow @ioshints on Twitter.