.
(backbone routers) . , , . - , , . , 1/1, , , SDH 155 / 622 /. - 12-14. , , , (hot swap) , -. Backbone Concentrator Node (BCN) Nortel Networks ( Bay Networks), Cisco 7500, Cisco 12000.
. , , . . , : 4-5. . . BLN, ASN Nortel Networks, Cisco 3600, Cisco 2500, NetBuilder II 3Com. , , .
, , . . , - Ethernet 10 /, - 64 /, 1,544 2 /. . . , , . , , ISDN, . . Nautika Nortel Networks, Cisco 1600, Office Connect 3Com, Pipeline Ascend.
( 3- ) . , , - , , 33,6 / 64 /. 10 /, 100 /. 3- CoreBuilder 3500 3Com, Accelar 1200 Nortel Networks, Waveswitch 9000 Plaintree, Turboiron Switching Router Foudry Networks.
.