...В чём-то может быть и кажется,на первый взгляд, пересечение.
Я,естественно, не со всеми стандартами работаю,но в тех,которые использую,часто заметно одно : ITU-T как-то более обобщённые,что-ли.
ETSI более детализированные,на мой взгляд.
Некоторые процедуры в ITU-T вообще вскольз упоминаются.
Я приводил цитату из ETSI ( нет, не ошибся я ).
Ниже привожу кусок чаптера побольше...
.........
ETSI
8.3 Time slots
There shall be a minimum of one and a maximum of sixteen 2 048 kbit/s links on a V5.2 interface. Each of these shall
have a layer 1 structured according to clause 4 and clause 5.
Time slots 16, 15 and 31 of each 2 048 kbit/s link may be used as physical communication channels and shall be
allocated as required by provisioning.
Time slots not provisioned as physical communications channels are available to be used as bearer channels under the
control of the BCC protocol.
8.4 Time slot allocation for physical communication channels
In the case of only one 2 048 kbit/s link, the time slot allocation for the physical C-channels shall be the same as that for
the physical C-channels in EN 300 324-1 [8]. This is to ensure full compatibility with V5.1.
In the case of more than one 2 048 kbit/s links forming a V5.2 interface then the protection protocol shall be used. In
this case, time slot 16 of the primary link will contain the protection protocol and any C-path which has been
provisioned to be within the same C-channel. Time slot 16 of the secondary link will also contain the protection
protocol.
Further physical C-channels should preferably be allocated in the following sequence;
- time slots 16 of the remaining 2 048 kbit/s links as required. If more are required, then;
- time slot 15 of a 2 048 kbit/s link. If still more are required, then;
- time slot 31 of the same 2 048 kbit/s link shall be allocated. If still more are required, then;
- continue the allocation by allocating time slot 15 and then 31 of the next 2 048 kbit/s link as indicated in the
previous subclause. This process may be repeated until all time slots 15 and 31 on all 2 048 kbit/s links have
been allocated.
ETSI EN 300 347-1 V2.2.2 (1999-12) 28
The above guidelines have been created to allow for maximum flexibility when allocating time slots as physical
C-channels whilst not constraining future service additions such as the ISDN H-channels. The allocation indicated above
need not be followed, in particular when either upgrading from V5.1 to V5.2, or when increasing the capacity of a V5.2
interface, as to follow these guidelines explicitly may result in a total rearrangement of the physical C-channels on a
V5.2 interface being required.
8.4.1 Data types for V5.2 C-paths
The following types of data have been defined which are conveyed over the V5.2 interface as communication paths:
a) p-type data: This is ISDN D-channel data with SAPI 16;
b) f-type data: This is ISDN D-channel data with SAPI = 32 to 62;
c) Ds-type: This is ISDN D-channel signalling type data with SAPI not equal to any of those above;
NOTE: It has been identified that services using previously reserved SAPIs may be provided in the future. Giving
a default allocation at least allows earlier implementations of V5.2 to transport these D-channel signalling
types across the AN although their future data type allocation may be changed.
d) PSTN: This is PSTN signalling information;
e) Control: This is control information data;
f) Link control: This is link control information data;
....
По V5.2 обычно на ETSI ссылаются,ITU-T-й рекомендации ,касающейся V.5 у меня нет по-просту...