Руководство Пользователя для Cisco Cisco Aironet 340 Ethernet Bridges
11 - 8 Aironet 340 Series Bridge
n The first 16 bits of the data portion contains a value that is greater
than the maximum data size (1518). The value is assumed to be a
protocol identifier that may be used to determine which protocol is
being used within the packet.
protocol identifier that may be used to determine which protocol is
being used within the packet.
n The first 16 bits of the data portion contains a value that is less than
the maximum data size. The value is interpreted as a frame length
and it is assumed that a IEEE 802.2 Logical Link Control (LLC)
header follows the length.
and it is assumed that a IEEE 802.2 Logical Link Control (LLC)
header follows the length.
The format of the LLC header is as follows:
DSAP, 8 bits, Destination Service Access Point (DSAP)
SSAP, 8 bits, Source Service Access Point (SSAP)
CTL, 8 bits, Control field
If the control field has a value 3 (for an un-numbered information
frame), then this header may be followed by:
frame), then this header may be followed by:
OUI, 24 bits, Organization Unique Identifier (OUI)
SAP-PROT, 16 bits, Protocol Identifier
You may set up filters based on either a protocol identifier or a DSAP/
SSAP combination. If the filter is based on SAPs and the control field
has a value of 3, the packet may also be optionally filtered based on the
OUI and LLC protocol fields.
SSAP combination. If the filter is based on SAPs and the control field
has a value of 3, the packet may also be optionally filtered based on the
OUI and LLC protocol fields.
Both types of filters may also use a variable length bit mask of the
packet contents to further specify which packets should be filtered.
packet contents to further specify which packets should be filtered.
Filter Protocols Menu
Option Value Description
1 - Default [ off ] - Default action
2 - Display - Display the protocol filters
3 - Add - Add a protocol filter
4 - Remove - Remove a protocol filter
5 - Length [ 22 ] - Length of packet data to log
6 - Monitor [ off ] - Protocol monitoring enabled
7 - Show - Show forwarded protocol list
8 - Clear - Clear forwarded protocol list
Enter an option number or name, “=” main menu, <ESC> previous menu
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