Interface Configuration Guide 7705 SAR Interfaces
Edition: 01 3HE 11011 AAAC TQZZA 71
3.2.1.6 Padding
On transmission, the Information field of the ending fragment may be padded with an
arbitrary number of octets up to the MRRU. It is the responsibility of each protocol to
distinguish padding octets from real information. Padding must only be added to the
last fragment (E-bit set to true).
3.2.1.7 FCS
The FCS field of each MP packet is inherited from the normal framing mechanism
from the member link on which the packet is transmitted. There is no separate FCS
applied to the reconstituted packet as a whole if it is transmitted in more than one
fragment.
3.2.1.8 LCP
The Link Control Protocol (LCP) is used to establish the connection through an
exchange of configure packets. This exchange is complete, and the LCP opened
state entered, once a Configure-Ack packet has been both sent and received.
LCP allows for the negotiation of multiple options in a PPP session. MP is somewhat
different from PPP, and therefore the following options are set for MP and are not
negotiated:
• no async control character map
• no magic number
• no link quality monitoring
• address and control field compression
• protocol field compression
• no compound frames
• no self-describing padding
Any non-LCP packets received during this phase must be silently discarded.
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