3Com MSR 50 Series, Руководство по настройке

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Configuring X.25 291
To meet the requirements of different networks, X.25 defines nine match types
and their relevant alias string formats, as shown in the following table.
2
Attributes related to the address code block in calling or called packets
As defined in the X.25 protocol, a call packet must carry the information set of
both the calling DTE address (source address) and the called DTE address
(destination address). This address information set is called the address code block.
While in call accept packet, some networks require that both (the calling DTE
address and the called DTE address) be carried, some networks require that only
one of the two be carried, while some others require that neither should be
carried. To adapt the difference between various networks, you can select as
required.
3
Default upper layer protocol that X.25 bears
An X.25 call request packet includes a CUD (Call User Data) field that indicates the
upper layer protocol type carried over X.25 protocol. When receiving an X.25 call,
the device will check the CUD field in the packet. If receiving a call carrying an
unidentifiable CUD field, the router will deny it. However, an upper layer protocol
can be specified as the default protocol on the X.25. When X.25 receives a call
with an unrecognizable CUD, it will treat it as the customized default upper layer
protocol.
Table 6 Alias match modes and meanings
Matching mode Description Example
free Free matching, the alias string
is in the form of 1234 1234" will match 561234, 1234567
and 956123478, but will not match
12354.
free-ext Extended free matching, in
which the alias string is in the
form of ...1234.. ...1234 .." will match 678123459, but
will not match 68123459, 67812345
and 6781234591.
left Left-most matching mode, in
which the alias string is in the
form of $1234 $1234" will match 1234567 and
12346790, but will not match
3123478 and 123784.
left-ext Extended left-most matching
mode, in which the alias string
is in the form of $1234... $1234 ..." will match 1234679 and
1234872, but will not match 123468
and 12346890.
right Rightmost matching mode, in
which the alias string is in the
form of 1234$ 1234$" will match 791234 and
6901234, but will not match 7912345
and 6212534.
right-ext Extended rightmost matching
mode, the alias string is in the
form of ....1234$
....1234$" will match 79001234 and
86901234, but will not match
7912345 and 506212534.
strict Strict matching mode, in
which the alias string is in the
form of $1234$ $1234$" can only match 1234
whole Whole matching mode, in
which the alias string is in the
form of ........ ........" will match all the valid X.121
addresses of 8 digits in length
whole-ext Extended whole matching
mode, in which the alias string
can only be * *" will match all the valid X.121
addresses