ATM 里封装类型中的SNAP意思[821考试]

Router# show atm pvc

           VCD/                                 Peak      Avg/Min   Burst

Interface  Name   VPI   VCI   Type   Encaps      Kbps         Kbps   Cells      Sts

2/0        1        0     5    PVC     SAAL    155000       155000               UP

2/0        2        0    16    PVC     ILMI    155000       155000               UP

2/0.2      101      0    50    PVC     SNAP    155000       155000               UP

2/0.2      102      0    60    PVC     SNAP    155000       155000             DOWN

2/0.2      104      0    80    PVC     SNAP    155000       155000               UP

2/0        hello    0    99    PVC     SNAP      1000                            UP

参考这个:

LLC and SNAP Encapsulation Using RFC 1483
RFC 1483, Multiprotocol Encapsulation over ATM Adaptation Layer 5,  
defines how various types of protocol data units (PDUs) are encapsulated for transport over ATM. 
RFC 1483 specifies two methods for doing so.
The most common method is LLC or SNAP encapsulation, 
in which multiple protocols can be carried over the same virtual connection. 
A standard LLC or SNAP header identifies the type of encapsulated packet. 
LLC encapsulation supports both routed and bridged protocols. 
The packet’s SNAP header identifies the type of protocol.