Optical/IP Networks

IP Management Gains Favor

A small group of software vendors is working to change the way devices send traffic through Sonet/SDH networks. And their efforts could result in cost savings for carriers -- that is, if equipment vendors can handle the change.

Background: For years now, Sonet/SDH networks have been managed with protocols based on Open System Interconnection (OSI), a suite of internetworking protocols originally developed by the International Telecommunication Union (ITU).

Sonet/SDH devices, such as ADMs, use a data communications channel (DCC) carried in the Sonet signal to send information to management and provisioning systems. These DCCs are part of a larger DCN (data communications network) that links the devices with the operations support systems in the carrier's network. This DCN setup lets operators access all Sonet network elements through a single connection into the network, one that allows for remote provisioning and centralized maintenance.

IP network devices, like routers, aren't based on these OSI protocols; instead, they use packet-oriented routing and management protocols established by the Internet Engineering Task Force (IETF). Each router or other IP-based device is managed via an IP-based control plane.

As IP plays an increasingly important role in carrier networks, particularly in metro networks where IP is used within or alongside Sonet/SDH rings, it's getting to be problematic to manage everything in a unified way. According to Chris Murton, founder and director of Murton Consultancy & Design Ltd., which specializes in helping carriers set up metro networks, the discrepancy is a cost factor for carriers, who'd like to start moving everything over to an IP-based management approach that doesn't require as much know-how to maintain as OSI does.

Murton says a suite of ITU protocols called G.7712 holds an answer. G.7712 defines a method of encapsulating OSI in IP and routing that information through a DCN. Over time, as IP devices proliferate, the OSI-based DCC can be removed altogether. But meanwhile, G.7712 provides an automated way to put OSI and IP management together, Murton maintains.

Murton says several vendors are at work on G.7712 code: Atos Origin, based in France, and Vertel Corp. (Nasdaq: VRTL), for example, presently offer software for OEMing by equipment vendors that purports to solve the OSI-to-IP management problem.

Cisco Systems Inc. (Nasdaq: CSCO) is also said to be at work on G.7712 software. But at press time, the vendor hadn't responded to inquiries about the status of its developments.

Vertel's VP of Asia/Pacific sales and operations, Koert Blom, says the market for this kind of software is just starting to form. "But I think by the middle of next year it will be mandatory," he says. Vertel is selling code to a range of equipment providers and has even conducted interoperability tests among its customers, but Blom can't identify who Vertel's worked with.

Using IP in Sonet/SDH management DCCs, the way G.7712 does, is a mixed blessing, according to Scott Clavenna, chief analyst at Heavy Reading, the market research division of Light Reading. "An IP-based DCC does a better job of supporting end-to-end management and provisioning," he says. But the problem is that the approach calls for a routing engine to be placed inside each network element, one that supports G.7712 or another form of OSI-to-IP conversion or encapsulation.

This can make for a "buggy" DCN, since each Sonet box in the network is also a router, and that can make for plenty of hiccups when routing tables aren't updated properly or nodes are added or taken out of service.

While vendors sort out the issues, carriers continue to face the cost of overlaying IP and its management over Sonet/SDH networks. The issues could take a long time to hammer out. In the meantime, the few suppliers presently working on the problem are surely apt to increase in number.

— Mary Jander, Senior Editor, Light Reading

To examine an executive summary of the Heavy Reading Report – "The Future of Sonet/SDH" – click here. The full report is available for $3,950.
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Tony Li 12/4/2012 | 11:13:40 PM
re: IP Management Gains Favor
The existing management structure is also packet based, only using CLNP. It also requires that all elements run IS-IS, effectively turning them all into routers at the management plane.

fw23 12/4/2012 | 11:13:39 PM
re: IP Management Gains Favor What a great article! This is a billion-dollar
market just waiting to be tapped by the right
people! Its just another example of companies
like Juniper just not "getting it" when it comes
to dealing with the RBOCs. No wonder so few
decision makers even know who they are.

I wish HEAVY READING would do an awareness
survey on G.7712 vendors. That would really
be useful to lots of decision makers who
spend lots of /brain-time/ on issues like

A G.7712 roadmap is a MUST for every vendor in
IP-land these days. Its another case of
get on the boat because if your not on the boat
when it sails you will be left on shore watching
the parade go by.
lr_monger 12/4/2012 | 11:13:37 PM
re: IP Management Gains Favor Tony

Isn't it the case that the SONET ADM and DACS network elements themselves are ES-IS type nodes ?

And that they are networked in the DCN with IS-IS routers ?


Tony Li 12/4/2012 | 11:13:36 PM
re: IP Management Gains Favor

I'm no expert on that side of the world, but my understanding is that an ADM is an IS. I would bet that a DACS is too.

While this is all working right now, the number of strange and wonderful hackery that has had to happen makes continued investment and maintenance of these systems much more expensive than necessary. There is, of course, a major cost to conversion, but for greenfield deployments, it would make a great deal of sense to use off the shelf technology as much as is practical.

Yoda88us 12/4/2012 | 11:13:36 PM
re: IP Management Gains Favor Don't forget that there are several hundred thousand deployed SONET/SDH systems supporting OSI for operations communications. This includes systems deployed over the last decade from Alcatel, Fujitsu, Lucent and Nortel, and no one is ripping these out.

Routing table updates remain a challenge in both the IP and OSI worlds. The key argument for IP is its relative ubiquity. However, after years of deployment, the OSI stack and options have been refined and work well in running SONET networks.
PO 12/4/2012 | 11:13:35 PM
re: IP Management Gains Favor Typically, yes, SONET NEs are deployed as Intermediate Systems. As I recall, there were some issues with deployment as End Systems (whether it was issues with spec interpretation, networking fit, or something else I'm not sure). Intervendor interworking was also better with IS-IS.

This legacy gear is one of the last battles which IP networking hasn't yet eliminated alternatives, although it is coming, as it should. There just isn't added value in OSI for this application, and the added costs of keeping two solutions can't be justified.

Now if only we can convince/educate the development teams within the various vendors that there's more to the world than OSPF Area Zero: there's still a number of design questions to get right.
christi 12/4/2012 | 11:13:34 PM
re: IP Management Gains Favor The old standard for SONET/SDH NEs was G.784.
This mandated CLNP over LAPD links routed with IS-IS.

G.7712 provides an option to go forward with IP. This includes both IPv4 and IPv6.
Basically it says that if IP is used it must be IP over PPP/HDLC routed with Integrated IS-IS as per RFC 1195 with RFC 3373 and RFC 2966. There is some other stuff in there which needs to be read before implementing, mostly around adjacency creation rules.

In order to get around the problems of getting IP through existing OSI-only infrastructure there are a number of tunnelling options in G.7712.

Manual tunnels can be built using GRE. For OSI over IP this is based upon RFC 2784 and for IP over OSI this is based upon RFC 3147.

I know that several vendors are working on both OSI over IP and IP over OSI tunnelling solutions, because they have talked to me about it.

If one wants to build manual tunnels then the IP and OSI routing needs to be kept apart. The bit that routes IP needs to be in one IS-IS area and the bit that routes OSI needs to be in a separate IS-IS area. A level-2 network may be built if wished that can route both with Integrated IS-IS.

Lastly there is an option in G.7712 for an automatic encapsulation option. This basically allows the ADMs themselves to tunnel the IP over OSI or the OSI over IP as and when needed. This is acheived using extensions to Integrated IS-IS.

Hope this helps,

The RFCs mentioned are available from the IETF, the URLs are:-

Philip Christian
Peter Heywood 12/4/2012 | 11:13:33 PM
re: IP Management Gains Favor No need to wait for an awareness survey. Why not start a list here of vendors working on G.7712 developments?

In this article, we list:

- Atos Origin
- Vertel Corp.
- Cisco (possibly)

If you know other vendors in this market, please post a message to tell the world about them.

beltway_light 12/4/2012 | 11:13:32 PM
re: IP Management Gains Favor
what is the relation of the below sited RFCs
to do with tis subject? like the OSPF does not
need 3way hellos?

The RFCs mentioned are available from the IETF,
the URLs are:-
christi 12/4/2012 | 11:13:31 PM
re: IP Management Gains Favor In order to be compliant with G.7712 an adm MUST support IP routing using Integrated IS-IS as per RFC 1195, 3373 and 2966. It may also support other routing protocols, but it MUST support Integrated IS-IS.

If the ADM supports OSI over IP then it MUST be as per RFC 2784.

If the ADM supports IP over OSI then it MUST be as per RFC 3147.

These are the RFCs that a vendor needs to follow in order to produce a G.7712 complaint ADM.

I suspect that many vendors will attempt to sell an ADM with only OSPF routing on it and claim that it is G.7712 compliant, however it would be a false claim. Buyer beware.
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