Cisco Networking Academy Chapter 6B

Use static routes to...

Connect to a specific network. Connect a stub router. Summarize routing table entries. Create a backup route.

Summary Static Route

If multiple lines of different specific networks point to the same exit interface or next hop, then a [blank] may be used to reduce cpu overhead and the size of the routing table.

Static routing has the following disadvantages...

Initial configuration and maintenance is time-consuming. Configuration is error-prone, especially in large networks. Administrator intervention is required to maintain changing route information. Does not scale well with growing networks; maintenance becomes cumbersome. Requires complete knowledge of the whole network for proper implementation.

By default, a directly connected network will have an administrative distance of what?

0

By default, static routes have an administrative distance of what?

1

Recursive Static Route

A [blank] route is a route whose next hop and the destination network are covered by another learned route in the Routing Information Base (RIB). Such static routes cannot be installed in the RIB because they are considered redundant routes.

Default Static Route

A default static is a rout that matches all packets. A default static rout is simply a static route with 0.0.0.0/0 as the destination IPv4 address.

Networks are subject to forces that can cause their status to change quite often:

An interface fails. A service provider drops a connection. Links become oversaturated. An administrator enters a wrong configuration.

In order to make a summary route you must do what?

Convert the networks into binary. Then combine them using a process similar to ANDing called Supernetting.

This type static route is configured with a higher administrative distance than the primary route.

Floating Static Route

Floating Static Route

Floating static routes are static routes that are used to provide a backup path to a primary static or dynamic route, in the event of a link failure. The floating static route is only used when the primary route is not available.

Configure a Floating Static Route

IPv4 static routes are configured using the ip route global configuration command and specifying an administrative distance. If no administrative distance is configured, the default value 1 is used.

Reach Remote Networks

Manually or Dynamically

Next-hop route

Only the next-hop IP address is specified

Directly connected static route

Only the router exit interface is specified.

Static routing has three primary uses and they are...

Providing ease of routing table maintenance in smaller networks that are not expected to grow significantly. Routing to and from stub networks. A stub network is a network accessed by a single route, and the router has only one neighbor. Using a single default route to represent a path to any network that does not have a more specific match with another route in the routing table. Default routes are used to send traffic to any destination beyond the next upstream router.

Manually Reaching Networks

Remote networks are manually entered into the route table using static routes.

Dynamically

Remote routes are automatically learned using a dynamic routing protocol.

Route Summarization

Route summarization, also known as route aggregation, is the process of advertising a contiguous set of addresses as a single address with a less-specific, shorter subnet mask. CIDR is a form of route summarization and is synonymous with the term supernetting.

Static routing provides some advantages over dynamic routing, including...

Static routes are not advertised over the network, resulting in better security. Static routes use less bandwidth than dynamic routing protocols, no CPU cycles are used to calculate and communicate routes. The path a static route uses to send data is known.

Standard Static Route

Static routing is a type of network routing technique. Static routing is not a routing protocol; instead, it is the manual configuration and selection of a network route, usually managed by the network administrator.

Fully specified static route

The next-hop IP address and exit interface are specified.

Default static routes are used...

When no other routes in the routing table match the packet destination IP address. When a router has only one other router to which it is connected. This condition is known as a stub router.

Common IOS troubleshooting commands include...

ping, traceroute, show ip route, show ip interface brief, show cdp neighbors detail

Useful commands to verify static routes...

ping, traceroute, show ip route, show ip route static, & show ip route network