Nortel Networks 8000 - Manual (Page 131)

Nortel Secure Router 8000 Series
Configuration -WAN Access 6 PPP and MP configuration
NCP negotiation supports IPCP, MPLSCP and OSCICP negotiations. IPCP negotiation
involves the negotiation of IP addresses of two ends. After NCP negotiation, a network layer
protocol is selected. The network layer protocol then sends messages over the PPP link.
The PPP link remains in communication state until a specific LCP or NCP frame closes this
link or some external events occur, for example, the intervention of users.
Packet compression
6.1.2 MP
The SR8000 supports the compression of the packet headers of IP, UDP, RTP, and TCP on the
PPP link layer.
Compression methods are as follows:
• Stac compression: You need CCP negotiation. This method compresses the whole IP
packets.
• TCP/IP header compression: You need IPCP negotiation. This method compresses only
TCP/IP packets header.
• PPP header compression: This method compresses the PPP packet header.
For details, refer to the Nortel Secure Router 8000 Series Configuration Guide - QoS.
Multilink PPP (MP) forms by binding multiple PPP links together to increase bandwidth. You
can apply it on the interfaces such as the serial interfaces and POS interface that supports PPP.
CÛ NOTE
You configure the E1 channel of the 16E1/T1 interface card for use in the clear channel mode, and
configure T1 to be in the clear channel mode, so that E1 and T1 can be carried out MP binding. The
SR8000 does not support the MP binding cross the card.
MP allows packet fragmentation. The fragmented packets send to the same destination
through multiple PPP links.
Implementation methods
Methods for SR8000 to support the MP configuration:
• MP-group
• Virtual-Template (VT)
03 NOTE
• On the SR8000, only the serial interface channelized by the high-speed interface cared implements
the MP binding through the MP-group type.
• Nortel recommends you to not configure many services, such as MP, L2TP and PPPoE, on the same
virtual template.
You can simultaneously bind an interface to MP-group and VT.
When you configure MP in the MP-group mode, you can directly add the physical interface to
the MP-group.
Configuring MP by VT involves as follows:
• Direct binding
Issue 5.3 (30 March 2009) Nortel Networks Inc. 6-5