Cisco Blogs

The Cisco Intercompany Media Engine – Open Federation ShowNotes

January 7, 2010 - 2 Comments

Robb Boyd Tina Shakour Opening Segment for TechWiseTV58

This show (now available on demand) is particularly intriguing to me in light of recent FCC filing by AT&T that state the regulations that keep the PSTN alive should be lifted, thus clearing the way for an all-broadband phone network. I believe this may be a very US-centric view, and there are many (very valid, IMO) objections to AT&Ts stance,  but it shows that the phone network as we know it, truly is evolving. In this episode we look at how Cisco is addressing “open federation”, a key component to borderless communication and a new way of communicating.

Segment 1: Islands of Advanced Communication

Inspired by “Glee” lately, we built out a cheer for “Collaboration is GREAT”:

Green: smaller equipment footprint (less e-waste); ability to reduce travel and commute times, etc.

Rich-media: Video of all sorts.

Enabling: Allows new methods of work-style; reaches employees who were formerly isolated due to remote work conditions

Actionable: Collaboration technologies are here now and build on your existing infrastructure.

Trust: Collaboration helps build trust. Not only trust in the people we can now see when we are speaking with them, but it also builds trust in the communication methods we use. We trust that the message gets through, we trust that when we reach out to someone, we are going to reach them on the device they prefer.

However, Collaboration today is most effective within an Enterprise. You get all these benefits across a campus, throughout an intranet, and globally for large companies. But what about those other groups you have to reach and build trust with? Customers, vendors, partners. . . . this is where Open Federation becomes the topic of conversation.


Open Federation has historically ran into a few key barriers to success:

Call Routing



Fault Management


In this show, we dig into each of these topics.


Segment 2: The Architecture of Open Federation


Jimmy Ray and Hakim Mehmood dig into the architecture of Open Federation

Hakim Mehmood

Hakim is the Product Manager for the Intercompany Meeting Engine (IME) and has over 15 years in the telecom industry, tracing his roots back to ISDN (there is some street cred there!). He spends some time with Jimmy Ray in the lab, laying out the major components of an open federation architecture:

Intercompany Media Engine

Cisco Unified Communications Manager 8.0 or Session Manager 8.0

ASA (Adaptive Services Appliance)

The Challenge with Open Federation - PSTN





Other essentials are basic PSTN and Internet connectivity, along with a account for certification authority.



Intercompany Media Engine Deployment Components


When you take these components together and look at the call flow of the architecture, what you get is this:


  • IME servers form a peer-to-peer network
  • Convert telephone numbers to a hashed 128-bit key
  • 1st call goes out the PSTN
  • After that call hangs up, information about this call is sent to the IME server
  • IME then asks the p2p network “who owns the number just called”?
  • When an answer is received, a verification process starts to ensure the other endpoint really owns that number
  • After verification, a ticket is produced
  • The 2nd call now goes across the IP network, using the ticket for routing information
  • Rich-media support is enabled


Key point for me is the fact that this was designed with security in mind: not only does it leverage the built-in features of the ASA, but the use of an outside certificate authority provides another layer of security and off-loads a process. In addition, this architecture is realistic and built for the “lowest common denominator” in PSTN and Internet connectivity.

IME Call Flow



Segment 3: Intercompany Media Engine: Open AND Scalable?


Kevin Roarty, engineer for the IP Communications Business Unit, joins Jimmy Ray in the lab to get into the details of distributed hash tables and how IME uses these make the magic of Open Federation happen. Why do we need distributed hash tables? Well – just how do the IME servers know where to send all those phone calls? If you are a routing geek, this segment is going to resonate with you. If you aren’t – enjoy the ride! This discussion is a deep one – one where Jimmy Ray busts out the pen on his new tablet and really digs into the details of how this all works with Kevin! This is some pretty amazing stuff and a segment I suspect will be watched over and over again as folks absorb the science behind all this. This is not your mom’s IP routing tables!

Kevin Roarty Explains Distributed Hash Tables


DHT Neighbors

 Segment 4: Intercompany Media Engine Hot Seat

 Segment 4 was my opportunity to slow down a bit and ask Hakim some of the questions that I hear most from the field …we jokingly referred to this as the ‘hot seat’ but I think the real value came in making sure we addressed the ‘lingering cynical questions you may have…’  Did we get them right?  What questions did I miss or did you think could use more explanation… drop me a note in the comments below!)

Hakim Mehmood on the Hot Seat

Marketing vs. Reality


Is this a Cisco lock-in? In other words, do I have to have a Cisco phone system for this to work?

– No. With Session Manager 8.0, we can front a legacy system and they can participate in the IME network.

IME is self-learning?

– Publication of numbers through the distributed hash tables and intelligence of the “ring” they are available to the other IME systems. (Re-watch Segment 3 for the details on this one!)

IME is global!

–  The base technologies are the Internet, PSTN, SIP and peer-2-peer which are globally available. However, the design of the architecture was built around the “worst level” of service for Internet and PSTN.

Claim: easy to deploy

– This does require UC 8.0 or Session Manager 8.0, this is an upgrade or a net-new install. Beyond this, most customers already have ASA or firewalling in place. Dial plans and phone numbers do not change for existing systems.

Why not just use SIP? How is this better?

– SIP requires a mapping of telephone numbers to SIP addresses. This is a manual process and one that will be time consuming.

What about policy? Can I enforce who can use this and who cannot?

– Policy can be strictly enforced: who in your enterprise can call other enterprises via rich media, which enterprises can be called and who can call your enterprise.


What does the future look like? (Watch the show for the answer to THAT one!) J



Segment 5: Open Federation and SIP

In this Segment, I joined Jimmy Ray in the lab to look deeper at SIP headers. As a fundamental compenent of the Open Federation architecture, a refresher in SIP is always good.


Jimmy Ray and I lament the “value” of H.323 then dive into the headers:

SIP Headers





Jimmy Ray then busted out the packet sniffer to look at a SIP packet:

SIP Packet Sniffer

I’m going to ignore his comment about email admins who’ve been promoted to VoIP engineers (here’s looking at YOU, my former employer where I toiled away on Exchange (version # withheld to protect the innocent).



Additional Resources:


Follow Hakim Mehmood’s IME blog on the Collaboration Community


IME product manager, Wade Hamblin, has some great articles and discussions on IME on the Collaboration Community


Segment 6

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  1. Hi Andrew – Yes, you can deploy SME 8.0 in front of a legacy system and join it to an IME ring. We realize not everyone has Cisco today and this is one of the main benefits of IME: the ability to leverage systems you already have in place. We are building a show right now on SME 8.0 which will air on May 6th.

  2. Hi Guys,Great show as usual, many thanks for putting this stuff on.As a Cisco partner based in the UK. I am keen to understand if Cisco currrently has any other voice vendors onboard with the whole IME piece.I am keen to exploit the technology to link educational establishments together using both existing kit at various sites geographically, and a mixture of hosted private cloud type sites/ clients. Because we can’t always be sure who is Cisco, are we saying we can deploy SME 8.0 to front an Avaya IP PBX or even a BT analogue system today?I am extremely keen to learn more about how I might position this technology to a series of stakeholders within the UK academic space and so guidance on ecosystem partners would be of excellent value.I really do appreciate your time and thanks again for the shows