Use HDLC protocol on the DDN line

I. Applicable conditions:

1. DDN is the main line, and PSTN is the standby line.

2. The HDLC protocol is used on DDN and the PPP protocol is used on PSTN.

3. dynamic routing can be performed on the main line or the standby line. In this example, dynamic routing is performed on the main line.

II,

Network Topology:

Iii. Solution description:

HDLC support is one of the most important new features of the vrouters of the BDA 3000 series. HDLC is a link layer protocol widely used in modern WAN technology. Its support for HDLC enables the BDCOM 3000 router to fully support common link layer protocols in China, thus broadening the application scope of the Boda router. The HDLC protocol of the Boda router supports TCP Header Compression and dynamic routing protocols RIP 1, RIP 2, and OSPF.

The central router connects to the DDN network through the E1 interface as the main line and uses the PSTN dial-up line as the backup line. dial-up connections are supported. The dot router accesses the DDN network through the ddnleased line and the PSTN through the dial-up line. Dynamic Routing is performed on the ddnleased line.

This solution has the following features:

1. When the local or remote ddnleased line is abnormal, a backup line is automatically set up.

2. the backup line follows the PPP protocol and supports telephone connection and selection on the central router. After the leased line is restored, it is automatically switched to the ddnleased line and the Modem is automatically suspended. For the PPP protocol, you can select the PAP and CHAP authentication protocols.

3. Dynamic Routing Protocols can be used on both the primary and standby routes.

4. When a backup line is used, a backup line is established only when there is data to be sent. When no data is sent at a certain interval, the router causes the MODEM to be suspended, A backup line is created when data is sent, which saves a lot of telephone fees.

5. You can set a multi-level password and firewall on the vro to prevent unauthorized users from logging on to the vro.

Iv. configuration instructions:

The configuration of the BDA router takes RIP V2 on the ddnleased line as an example:

* Ent

# Config

Config # nodename bdcom

Bdcom_config # rip enable
Bdcom_config # s0

Bdcom_config_s0 # enca hdlc

Bdcom_config_s0 # ip add 140.1.1.2 255.255.0.0

Bdcom_config_s0 # map add 140.1.1.1 broadcast

Bdcom_config_s0 # rip version 2

Bdcom_config_s0 # quit

Bdcom_config # s1
Bdcom_config_s1 # enca ppp
Bdcom_config_s1 # line dial
Bdcom_config_s1 # ip add 150.1.1.2 255.255.255.0.0
Bdcom_config_s1 # map add 150.1.1.1 23232323
Bdcom_config_s1 # quit
Bdcom_config # route add 130.1.0.0 255.255.0.0 140.1.1.1 2
Bdcom_config # route add 130.1.0.0 255.255.0.0 150.1.1.1 5
Bdcom_config # rip network add 140.1.0.0
Bdcom_config # rip redistribute connected
Bdcom_config # write

5. Notes:

1. This solution also supports dynamic routing on the backup line at the same cost.

2. The broadcast option must be added to the map on the main line. Otherwise, dynamic routing will not be broadcast.

3. Set two static routes on the vro. The cost of the main line is as follows: metric = 2) The cost of the primary line is smaller than that of the standby line, for example, metric = 5 ).

If you use a back-to-back line to simulate DDN, a certain vro shall provide the clock and specified speed.