American Fibertek SM24p-PoE Manuel d'instructions télécharger pdf (Page 31)

User Manual

Rev.A1

1-Mar-11

comprises four fields, DSAP, SSAP, Control and Information. The DSAP address

field identifies the one or more service access points, in which the I/G bit indicates it

is individual or group address. If all bit of DSAP is 1s, it’s a global address. The

SSAP address field identifies the specific services indicated by C/R bit (command or

response). The DSAP and SSAP pair with some reserved values indicates some

well-known services listed in the table below.

0xAAAA SNAP

0xE0E0 Novell IPX

0xF0F0 NetBios

0xFEFE IOS network layer PDU

0xFFFF Novell IPX 802.3 RAW packet

0x4242 STP BPDU

0x0606 IP

0x9898 ARP

Table 3-2

LLC type 1 connectionless service, LLC type 2 connection-oriented service

and LLC type 3 acknowledge connectionless service are three types of LLC frame

for all classes of service. In Fig 3-2, it shows the format of Service Access Point

(SAP). Please refer to IEEE802.2 for more details.

Fig. 3-2 SAP Format

1 2 ... 26 27 28 29 30 31 32 33 34 35 36 ... 124 125

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American Fibertek SM24p-PoE Manuel d'instructions Page 31