, , :
;
.
(backbone wide-area networks) , . , . , , , (business-critical applications). . , .
2 622 /, IP, IPX SNA IBM, frame relay, ATM, X.25 TCP/IP. , . 6.5.
. 6.5.
, . , . . , (telecommuters - ), , , , , .
, , . .25, .
, . , , , . , , . , - , ( , ).
|
|
, ISDN - frame relay. 19,2 64 /. Internet. Internet , , .
, , . .
(Remote Access Server, RAS). - , , . , . ISDN.
. 6.5. , , . , (, SDH 155-622 /), (, frame relay) .
(WAN) : - , , .
, , : , (), -, , , .
: ISDN, B-ISDN. , , , . , , , , , . - - - , , - .
|
|
, . : - -, - , . Internet , intranet.
, , : DTE, , DCE, .
: - (UNI) - (NNI). UNI . NNI , .
, . , . , .
- (.25, frame relay, ) . .
.