Chapter 13 Routing Protocols

 

Table 94 Network > Routing Protocol > RIP (continued)

 

LABEL

DESCRIPTION

 

MD5

This field is available if the Authentication is MD5. Type the ID for MD5

 

Authentication

authentication. The ID can be between 1 and 255.

 

ID

 

 

MD5

This field is available if the Authentication is MD5. Type the password for MD5

 

Authentication

authentication. The password can consist of alphanumeric characters and the

 

Key

underscore, and it can be up to 16 characters long.

 

 

 

 

Redistribute

 

 

 

 

 

Active

Select this check box to advertise routes that were learned from the indicated

 

 

Name.

 

 

 

 

Name

This field displays other sources of routing information that the ZyWALL can

 

 

advertise in the RIP network.

 

 

 

 

Metric

Type the cost for routes provided by the indicated source. The metric represents

 

 

the “cost” of transmission for routing purposes. RIP routing uses hop count as the

 

 

measurement of cost, with 1 usually used for directly connected networks. The

 

 

number does not have to be precise, but it must be between 0 and 16. In practice,

 

 

2 or 3 is usually used.

 

 

 

 

Apply

Click this button to save your changes to the ZyWALL.

 

 

 

 

Reset

Click this button to return the screen to its last-saved settings.

 

 

 

13.3 The OSPF Screen

OSPF (Open Shortest Path First, RFC 2328) is a link-state protocol designed to distribute routing information within a group of networks, called an Autonomous System (AS). OSPF offers some advantages over vector-space routing protocols like RIP.

•OSPF supports variable-length subnet masks, which can be set up to use available IP addresses more efficiently.

•OSPF filters and summarizes routing information, which reduces the size of routing tables throughout the network.

•OSPF responds to changes in the network, such as the loss of a router, more quickly.

•OSPF considers several factors, including bandwidth, hop count, throughput, round trip time, and reliability, when it calculates the shortest path.

•OSPF converges more quickly than RIP.

Naturally, OSPF is also more complicated than RIP, so OSPF is usually more suitable for large networks.

OSPF uses IP protocol 89.

OSPF Areas

An OSPF Autonomous System (AS) is divided into one or more areas. Each area represents a group of adjacent networks and is identified by a 32-bit ID. In OSPF, this number may be expressed as an integer or as an IP address.

There are several types of areas.

•The backbone is the transit area that routes packets between other areas. All other areas are connected to the backbone.

 

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ZyWALL USG 100/200 Series User’s Guide