Avocent Cyclades-PR4000 installation manual Routes, Seq Rule Message From Tele Popeye Route Map

Cyclades-PR4000

STEP FOUR

An access list needs at least one rule. The example in Figure 12.6 shows three access lists, each one with several rules. Each neighbor can be assigned up to 6 access lists, as seen in step 2.

Discarded	Discarded	Discarded
Routes	Routes	Routes

BGP-4

Seq. 10 Seq. 4 Seq. 2 Rule 1 Rule 0 Rule 2 Rule 1 Rule 0 Rule 2 Rule 1 Rule 0

Message From

Tele Popeye

Route Map	Access list	Access list	Access list
	popeye_comm	popeye_dist	popeye_path
	type Community	type Distribution	type AS Path

FIGURE 12.6 UPDATE MESSAGE ARRIVING FROM TELE POPEYE PASSING THROUGH 3 FILTERS AND

A ROUTE MAP

An update message arriving from the neighbor called Popeye in step 2 will pass through the filters assigned to it in the Neighbor Menu. The figure shows the case where the scope of the list is permit and that of the rules is deny. Each rule causes routes to be discarded until finally the shortened message arrives at the route map (if one has been configured for this neighbor).

Chapter 11 - Routing Protocols 109