Routing Protocols Overview; What You Need To Know; The Rip Screen - ZyXEL Communications ZyWall USG20-VPN User Manual

10.5 Routing Protocols Overview

Routing protocols give the USG routing information about the network from other routers. The USG
stores this routing information in the routing table it uses to make routing decisions. In turn, the
USG can also use routing protocols to propagate routing information to other routers.
Routing protocols are usually only used in networks using multiple routers like campuses or large
enterprises.
• Use the RIP screen (see
and/or send routing information.
• Use the OSPF screen (see
manage OSPF areas.
• Use the OSPF Area Add/Edit screen (see
area.

10.5.1 What You Need to Know

The USG supports two standards, RIP and OSPF, for routing protocols. RIP and OSPF are compared
here and discussed further in the rest of the chapter.
Table 95 RIP vs. OSPF
Network Size
Metric
Convergence
Finding Out More
See Section 10.8 on page 248

10.6 The RIP Screen

RIP (Routing Information Protocol, RFC 1058 and RFC 1389) allows a device to exchange routing
information with other routers. RIP is a vector-space routing protocol, and, like most such
protocols, it uses hop count to decide which route is the shortest. Unfortunately, it also broadcasts
its routes asynchronously to the network and converges slowly. Therefore, RIP is more suitable for
small networks (up to 15 routers).
• In the USG, you can configure two sets of RIP settings before you can use it in an interface.
• First, the Authentication field specifies how to verify that the routing information that is
received is the same routing information that is sent. This is discussed in more detail in
Authentication Types on page
• Second, the USG can also redistribute routing information from non-RIP networks, specifically
OSPF networks and static routes, to the RIP network. Costs might be calculated differently,
however, so you use the Metric field to specify the cost in RIP terms.
• RIP uses UDP port 520.
Chapter 10 Routing
Section 10.6 on page
Section 10.7 on page
RIP
Small (with up to 15 routers) Large
Hop count
Slow
for background information on routing protocols.
248.
USG20(W)-VPN Series User's Guide
239) to configure the USG to use RIP to receive
241) to configure general OSPF settings and
Section 10.7.2 on page
OSPF
Bandwidth, hop count, throughput, round trip time and
reliability.
Fast
239
245) to create or edit an OSPF