Nokia M1122 - Manual (Page 22)

E Copyright Nokia Networks Oy C33906001SE_00 2-11
Figure 2-5 Choosing the VCC2 for tunneling example
2.2.8 Point-to-Point Protocol over Ethernet (PPPoE)
Standard PPPoE mode is used when M1122 is operating as a bridge.
PPPoE protocol defines how PPP sessions are mapped into Ethernet
packets. When M1122 operates as a bridge, this protocol is transparent
to M1122.
2.2.9 Payload encapsulations
Both routed and bridged protocols are encapsulated in the ATM link by
using either RFC 2684 LLC/SNAP encapsulation or VC multiplexing.
M1122 also supports PPP over AAL5 encapsulation, in which routed
protocols are first encapsulated in PPP (RFC 1661). PPP is then
encapsulated in ATM according to the IETF PPP over AAL5 using
RFC 2364 VC multiplexing or LLC/NLPID encapsulation.
2.2.10 Weighted Fair Queueing (Class of Service)
As a Class of Service (CoS) function, M1122 supports Weighted Fair
Queueing (WFQ) for each ATM VCC. The CoS function ensures that
different IP traffic flows are treated fairly in the upstream (towards the
Internet) direction. This may be necessary, in some cases, because the
upstream capacity of the ADSL line is somewhat limited compared to
the Ethernet bandwidth on the office or home LAN. The WFQ CoS