SS7 Archives

ISDN User Part – ISUP

The ISDN User Part – ISUP is responsible for setting up and releasing trunks used for inter-exchange calls. As its name implies, ISUP was created to provide core network signaling that is compatible with ISDN access signaling. The combination of ISDN access signaling and ISUP network signaling provides an end-to-end transport mechanism for signaling data between subscribers. Today, the use of ISUP in the network has far exceeded the use of ISDN on the access side. ISUP provides signaling for both non-ISDN and ISDN traffic; in fact, the majority of ISUP-signaled traffic currently originates from analog access signaling, like that used by basic telephone service phones.

The primary benefits of ISUP are its speed, increased signaling bandwidth, and standardization of message exchange. Providing faster call setup times than Channel Associated Signaling (CAS), it ultimately uses […]

SS7, VOIP|

Message Transfer Part 3 – MTP3

Level 3 of the Message Transfer Part (Message Transfer Part 3 – MTP3) resides at layer 3 of the OSI model and performs the SS7 protocol’s network functions. The primary purpose of this protocol level is to route messages between SS7 network nodes in a reliable manner. This responsibility is divided into two categories:

Signaling Message Handling (SMH)
Signaling Network Management (SNM)

[…]

SS7, VOIP|

Message Transfer Part 2 – MTP2

Message Transfer Part 2 – MTP2 corresponds to OSI Layer 2 (the data link layer) and as such is the lowest protocol in the stack. Sitting on the physical layer, it provides a reliable means of transfer for signaling information between two directly connected signaling points (SPs), ensuring that the signaling information is delivered in sequence and error-free.

[…]

SS7, VOIP|