The
Backhaul PoP is one point in the network to implement this traffic shaping function for
downstream traffic2 as this allows for the traffic shaping parameters (reserved bandwidth
for each traffic type, flow priorities) to be tuned to the available injection layer capacity.
The available capacity can be expected to vary for each branch due to the employment of
P2P and P2MP technologies that best meet the distance and foliage penetration
requirements at each site. Besides traffic shaping, the Backhaul PoP also lends itself for
network partitioning at layer 3 in order to manage the control traffic associated with
roaming users. The entity responsible for traffic shaping and roaming is called the branch
router.
The NOC shown in Figure 13.1 aggregates all user traffic and is responsible for
traffic routing, subscriber-related administration functions as well as various network
element management functions. An Access Controller (AC) acts as the layer 3 router for
client IP traffic between the backhaul network and the NOC subnet. Outbound IP traffic is
masqueraded by the AC and forwarded to the NOC??™s Internet router. The AC also manages
the dynamic assignment of IP addresses to 802.
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