Understanding the network.pdf - Back to Home

1.544Mbps. The actual transport link is either a permanent or switched virtual
circuit (PVC/SVC), with the former being the most common provisioning
implementation.
Because FR PVC is still the most common implementation, we will focus our
examples on FR PVC configuration. Configuring a FR PVC has three basic steps:
1. The interface must be enabled to use FR encapsulation, using the interface
configuration subcommand:
2.
3. jupiter(config)# interface serial0
4. jupiter(config-if)#encapsulation frame-relay
5.
6. After encapsulation is set, the Data-Link Connection Identifier (DLCI) and
Local Management Interface (LMI) type need to be configured. The DCLI is
set using the FR interface configuration subcommand . The LMI type can be configured dynamically (on
IOS versions 11.2 and later) by the router when the interface is activated or
the LMI can be set explicitly in the routers FR interface configuration. The
default LMI is Cisco. IOS supports three LMI types: ansi (most often used),
cisco, and q933a. Let's look at Jupiter's DCLI and LMI configuration:
7.
8. jupiter(config-if)#frame-relay interface-dcli 35
9. jupiter(config-if)#lim-type ansi
10.
11. The last step is the configuration of the Layer 3 protocol address assignment.
FR supports four different network topologies: point-to-point, meshed and
partially meshed point-to-point, and multipoint. We will look at meshed and
multipoint topologies in a moment. If you are only running IP over a FR
point-to-point connection, it is possible to configure the interface to use
either unnumbered IP or static IP address assignments. With unnumbered IP,
one router appears as a DTE and the other as a DCE. You should recall that
the IP address of one of the router's IP configured Ethernet interfaces is used
to exchange IP datagrams across the link. Alternatively, if you are using the
point-to-point FR connection for multiprotocol transport, it is best to assign
Layer 3 addresses for all the protocols. Here is an example of a
point-to-point interface using AppleTalk and IP and static Layer 3 to DCLI
mappings:
12.
13. jupiter(config-if)#ip address 172.16.33.1 255.255.255.252
14. jupiter(config-if)#appletalk cable-range 6678-6678 6678.1