Cisco Octal-Port DMT ATU-C Line Card Manual do Utilizador descarregar pdf (Página 13)

188 Chapter 8: Using DSL to Access a Central Site

Step 5

Assign a network interface to a bridge group:

bridge-group

Step 6 Enables a bridge group virtual interface:

interface bvi

bridge-group

Example 8-9 demonstrates the IRB conﬁguration of the Cisco 6400 NRP.

RBE Overview

When conﬁgured for RBE, the CPE conﬁguration remains the same as that in IRB. RBE is

intended to address most of the RFC 1483 bridging issues, such as broadcast storms and

security. The ATU-R behaves like the routed-bridge interface that is connected to an Ethernet

LAN. For packets sending from the customer side, the destination IP address is examined,

and the Ethernet header is skipped. If the destination IP address is in the route cache, the packet

is fast-switched to the outbound interface. If the destination IP address is not the route cache,

the packet is queued for process switching.

For packets destined for the customer devices, the destination IP address is examined ﬁrst,

and then the destination interface is determined from the IP routing table. To place a

destination MAC address in the Ethernet header, the router checks the ARP table for that

interface. If the MAC address is not found, the router generates an ARP request for the

destination IP address and forwards the ARP request to the destination interface only. If an

unnumbered interface is used and multiple subscribers are on the same subnet, the routed-

bridge interface uses proxy ARP. All of these can be achieved without using a bridge group

or BVI in the aggregation gateway and therefore are more scalable. Figure 8-6 illustrates

the RBE protocol stack.

Example 8-9 IRB Conﬁguration

bridge irb

bridge 1 protocol ieee

bridge 1 route ip

interface ATM0/0/0.133 point-to-point

description Integrated

no ip directed-broadcast

pvc 1/33

encapsulation aal5snap

bridge-group 1

interface BVI1

ip address 10.1.1.1 255.255.255.0

0732x01.book Page 188 Monday, November 17, 2003 2:49 PM

1 2 ... 8 9 10 11 12 13 14 15 16 17 18 ... 49 50

Sem comentários

Cisco Octal-Port DMT ATU-C Line Card Manual do Utilizador Página 13