The Telecom Protocols

Capability Exchange: When two peers established transport connection, they must exchange the capability exchange message. this message allows the discovery of peer's identity and its capabilities. Once transport layer is established, CER and CEA exchanged to determine the capability of peer endpoint followed by DWR/DWA. In below example DiameterNodeA start diameter connection with DiameterNodeB after transport layer connection established. In case of TCP (Syn/Syn-Ack) and  SCTP (Init/Init-Ack/Coockie Echo) exchanged. In case of SCTP Connection establishment(CER, CEA, DWR, and DWA) are exchanged with setting out-of-order delivery false to avoid race-condition and for connection termination (DPR/DPA) set the timer to receive out-of-order message before terminating the connection.               DiameterNodeA                     DiameterNodeB   ...

    Diameter is AAA (authentication, Authorization, and Accounting protocol) such as RADIUS protocol. As name suggest, DIAMETER is double of RADIUS protocol. while there are many difference between two protocols but one of the main difference is diameter provides the security and reliability because diameter uses TCP/SCTP on transport level, it uses TLS and DTLS. whereas RADIUS runs over the UDP.   Diameter protocol is peer to peer protocol so that any node can initiates a request, all data delivered in form of AVPs and provides following facilities:   - Ability to exchange messages and deliver AVPs. - Capability Negotiation - Error Notification - Application specific services.     Diameter base protocol is run on port 3868 for both TCP and SCTP. TLS and Datagram Transport Layer Security (DTLS) uses port 5658. It is assumed TLS run on top of TCP and DTLS is run on top of SCTP. When no transport connection availa...

BICC Bearer establishment procedures: Four variants of BICC IP bearer set-up procedures are defined: -             Fast Forward -             Delayed Forward -             Fast Backward -             Delayed Backward  Those procedures differ on the way the bearer control information are exchanged, and on whether an APM (Connected) message shall be sent by the originating BICC node once the bearer is ready for use. -             Bearer control information exchanges : -             In Fast bearer setup (forward or backward) and in delayed forward bearer establishment procedures, the IP bearer establishment is done in the ...

H.248   is protocol used between the MGC and MG in Master-Slave fashion. MEGACO is similar to MGCP. MGC uses this protocol to control the MG. MEGACO  provide the following enhancement over the MGCP. - Support multimedia and multi point conference enhanced service. - Improve syntax for more efficient semantic message processing. - TCP and UDP transport support - Support either binary or text encoding. Message Structure: Message {  Transaction {     Action {         Command {            Descriptor {                Package {                     Property { }}}}}} MTACDPP … Message : Multiple Transactions can be concatenated into a message, which contains header, the version...

Session Initiation Protocol (SIP) SIP stack handled over the following layer and data transfer based on following Internet Media Protocol stack: Application Layer: H.232, SIP, RTP, DNS, DHCP Transport Layer: TCP, UDP Internet Layer: IP Physical Layer: ATM, V90, Ethernet, Wireless 802.11 1. Physical Layer : it can be following:         - Ethernet LAN,         - DSL,         - ATM         - Wireless 802.11 network. 2. Internet Layer : used to route the packet across the network using the destination IP address. IP offers following functionality and drawbacks with simplicity:  -- Connection less  -- Best-effort packet delivery protocol.  -- IP packets can be lost  -- IP packets can be delayed  -- IP packets cab be received out of sequence.  -- IP packet are not Acknowledged. IP Address used over the public internet are assigned in blocks by the IANA (I...