|
Fl« (1 Bywh |
urn act (Î 0*1*5) |
Unrumbcfod Ê-fonTOlian IndKtfix (i Byiö) |
Prctorafl DiscrrTtnulor HiByi») |
faUmmca (1 Byic) |
íVjiKiljkil |
PCS |
Fita i'Bïl») |
|
Table 15-8. LMI Frame Format Field Description | |
|
Field |
Description |
|
Flag |
Delimits the start and end of the LMI frame. |
|
LMI DLCI |
Identifies the frame as an LMI frame rather than a Frame Relay data frame. The DLCI value is dependent on the LMI specification used; LMI (original) uses DLCI 1023, LMI (Annex A) and LMI (Annex D) use DLCI 0. |
|
Unnumbered Information Indicator |
Sets the poll/final bit to zero (0). |
|
Protocol Discriminator |
Always contains a value indicating that the frame is an LMI frame. |
|
Call Reference |
Always contains zeros. This field is currently not used for any purpose. |
|
Message Type |
Labels the frame as one of the following message types: • Status-inquiry message— Allows a user device to inquire about the status of the network. • Status message— Responds to status-inquiry messages. Status messages include keepalive and PVC status messages. |
|
Information Elements |
Contains a variable number of individual information elements (IEs). IEs consist of the following fields: • IE Identifier— Uniquely identifies the IE. • Data— Consists of one or more bytes containing encapsulated upper-layer data. |
|
Frame Check Sequence (FCS) |
Ensures the integrity of transmitted data. |
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