1、CCITT FASCICLE 111.7 88 I 48b259L 0504504 9 Access channel control Signalling and OAM (Notes 1 and 2) c) Access Virtual call control (Notes 1 and 3) Signalling and OAM User information 1.451 1.441 1.430 Channel and rate W64) I 1.451 1.441 1.430 Channel and rate Protocols D(l6) 1.45 1 1.441 1.431 1.4
2、5 1 1.441 1.431 D(64) I I Channel and rate Protocols X.25, L3 X.25, L2 1.430 X.25, L3 X.25, L2 1.431 X.25, L3 1.441 1.430 I X.25, L3 W64) 1.441 1.431 Provision Protocols X.25, L3 X.25, L2 1.430 X.25, L3 X.25, L2 1.43 1 A A X.25, L3 A 1.441 1.430 X.25, L3 A 1.441 1.431 LI, L? and L3 Note I - The defi
3、nition of other protocols for OAM is for further study. Note 2 - The protocols listed in this column are for establishing communications with the packet handling function using out-of-band call control signals. This procedure does not apply in certain cases (for example, semi-permanent D-channel con
4、nection). Nore 3 The protocols listed in this column are for the establishment of a virtual circuit using X.25 procedures. These procedures do not apply to permanent virtual circuits. Layer 1, layer 2 and layer 3 1.9 Djwamic description Dynamic descriptions for the Recommendation 1.462 procedures in
5、 the virtual call and permanent virtual circuit bearer service category are for future study. State transition diagrams for layer 3 of Recommendation X.25 (Annex B) apply for virtual call and permanent virtual circuit. 2 1.232.2 - Connectionless bearer service category No/e - This connectionless bea
6、rer service category is a different concept from, and should not be confused with, the OS1 Connectionless Mode Network Service. Thus, the name of this service may change as the service is better defined. Further aspects of this bearer service category are for further study. 3 1.232.3 - User signalli
7、ng bearer service category Note - This service is different from, and should not be confused with, the user-to-user signalling supplementary service (see Recommendation 1.257). The user-to-user signalling supplementary service is used in conjunction with either a bearer service or a teleservice. The user signalling bearer service category stands on its own and is not used in conjunction with a bearer service or a teleservice. Further aspects of this bearer service category are for further study. 172 Fascicle 111.7 - Rec. 1.232 -ppp-
