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ss7 in voip

Viewing 15 posts - 1 through 15 (of 24 total)
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  • #20886

    I want to know about ss7 in voip

    James Ballash

    You may want to check out ITU RFC H.248 regarding MEGACO.


    Thakyou very much. If you have got any information about ss7 over ip. Iam really want you exchange it with me.
    one again thankyou very much

    iliana Damianova

    i want to know how Media Gateway Controller connect with Gatekeeper, Madia Gateway, what does protocols use in H.323 network


    Hmmm…ss7 and voip very interesting….Megaco does get you there, but vendors have figured out other ways to do it also with other protocols SS8, Cisco, Nuera etc…
    Are you wondering how to transport ss7 over IP? There are many issues on that front, such as variant to variant interworking, parameter transparency. etc…
    look around on stuff re SCTP, M3UA, SUA etc…
    Go to the sigtran working group in the IETF.

    Iliana –
    MGC to GK interworking would depend on the MGC, if it supported H.323 or not. It would have to use H323 unless you had some sort of protocol converter.


    I have got trouble about deffident
    ss7 sip mgcp h323 and relation among them.Could you help me.


    All are signaling protocols. They do essentially the same things on different networks.

    Interworking is another issue.

    James Ballash

    h.323 and SIP are signalling protocols. MGCP and Megaco are control protocols. Many group are working on integrating 323 and SIP. H.323 so far has won. SIP is very new and requries a proxy server. (more equipment) SS7 is used as the standard for inter office communications between PSTN offices. MGCP was to use ss7 data setup infrastructure but VoIP for voice transport.


    R, do you thing sip mgcp,h323 exit in a network.


    James Ballash, may you tell me relationship betwen ss7and MGCP, SS7 and H323, SS7 and sip.


    Okay…i chose the wrong term. SIP and h.323 use a distributed model with intelligent endpoints which can make decisions. The common thread for all these “signaling” protocols is that they all help with:
    -establishing media connection
    -teardown of media connection
    -modification of media connection

    H.323 came from the ITU.
    H.225 for call signaling
    RAS to define GK communication
    H.245 for media negotiation
    GK is an optional component added for additional control as well as scale.

    SIP came from the IETF RFC2543. Leverages work done in other drafts and leverages existing Internet protocols. i.e. SMTP headers. Optional components of SIP are: Redirect, Registrar, Proxy, Location servers. SIP does not require a proxy as a proxy is an optional component in RFC2543. This has not changed in any of the bis supplements I have seen thus far.

    MGCP/Megaco/H.248/IPDC/SGCP are all control type protocols where the endpoints are dumb and must be told what to do. This requires a call agent or media gateway controller. Whatever you want to call it.

    SS7 is based on ITU Q.700-709
    Q.710 for MTP
    Q721-725 for SCCP
    Q730 TUP
    Q771-775 ISUP
    Q791-795 TCAP
    and a few others.
    MTP defines the first 3 layers of the OSI model for the signaling links.
    ISUP provides the call control function for circuits.
    SCCP is kind of like the TCP/UDP for TCAP and higher protocl layers.
    TCAP communications to network databases


    How do they relate? They don’t. They must all be interworked into each other in order to define the media path. SS7 controls pstn networks, which can then go to a voice over IP gateway which can use any of the IP based protocols. How do they interwork? That would depend on the who built the box. Most still have to figure out how to get SS7 transparency in order to pass the necessary fields through to the far end pstn. I could go on for days but am running out of time. If you have specific questions please post


    My subject is ss7 over IP I think ss7 , SIP, MGCP ,H.323 have got peer role. Do you think so?
    I think in a network have got all them one of them conect two element deffident.
    Thank you very much when you enjoy the subject with me.


    I guess you can say they have peer roles, but they are just different. They control different networks. At the end of the day protocols are just protocols, It is simply the language the devices use to communicate.

    You have your native language as do I, in order for us to work efficiently together we must speak a common tongue(In this case english). They probably wouldnt sit all in a single network with protocol translation going on somewhere, but the are more like todays global communication.

    In France, folks speak french, just as in spain they speak spanish and in the UK they speak english. How do folks understand each other though when they want to communicate? They speak a common tongue, maybe they all speak french or maybe they all speak english or spanish, it doesnt matter. All that matters is that they understand each other in order to get the data across. This is the same with VoIP networks.

    I could have a SIP network, h323, ss7 as well as MGCP network, but none of them can work together until they speak a common tongue. You will see that most VoIP gateways speak the common tongue of TDM on one side. It could be E1 PRI, T1 PRI, E1-R2 (variant) or T1-CAS, whatever it doesnt matter as long as the attached switch understands it. Same with VoIP, a 323 network cannot speak to a SIP network natively, they must use some sort of protocol translator or the endpoint must understand both protocols.

    MGCP is a different story, since one element (call agent) is “controlling the whole network, it must understand either SIP or 323 in order to talk with those networks. Call Agents cannot speak MGCP to each other because they are peers and MGCP is designed as a master slave type relationship.

    Hopefully that clears it up, if you have any further questions feel free to email


    May be you khow more, I think it deffirentbut but they can enterchange over gateway so they can work together in a network.

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