Advantages And Disadvantages Of Routing Protocols - HP 7102dl - ProCurve Secure Router Configuration Manual

IP Routing—Configuring RIP, OSPF, BGP, and PBR
Overview
N o t e
Protocol Advantages
RIP • Configuration is simple.
• RIP v2 can communicate with
an external network.
OSPF • Accurate routes take link
speed and cost into account.
• Convergence is fast.
• Overhead is as low as RIP if
the network is well-designed.
15-10

Advantages and Disadvantages of Routing Protocols

Dynamic routing can provide reliable routes. OSPF, for example, can select
routes according to fairly sophisticated criteria, such as link state and band-
width, and BGP can take an organization's policies into account. The best
route at one moment may not always be the best route, and dynamic routing
protocols can track these changes. Dynamic routing also adapts well to
changes in network topology, including node failures as well as network
expansion.
On the other hand, routing protocols consume bandwidth as routers exchange
updates and CPU processes as routers calculate the best routes. In addition,
a router that has been carelessly configured may send updates to unauthorized
devices, creating a security vulnerability. However, a well-designed network
eliminates many of these problems.
You should not use a dynamic routing protocol, particularly RIP, over a dial-
up connection because the period updates may keep the connection open
longer than necessary—costing your organization money.
Table 15-2 lists some advantages and disadvantages of each protocol. As you
can see, different protocols provide different best uses. You can use protocols
in conjunction with each other. For example, a router can run OSPF on the
private network and BGP to connect to the Internet.
Table 15-2. Advantages and Disadvantages of Routing Protocols
Disadvantages
• Convergence is relatively
slow.
• Metric is based only on hop
count.
• If used to connect to an ISP,
the ISP must redistribute the
routes into BGP.
• Configuration is complicated.
• Overhead can be high.
• OSPF cannot be used as an
EGP without redistribution.
Uses
• LANs
• Simple WANs
• Connecting to an external
network
• Not used over dial-up
connections
• More extensive LANs and
WANs
• Not used over dial-up
connections