Snapshot routing is enabled through
interface configuration commands .
The central router is configured for snapshot routing by applying
the snapshot server interface
configuration command to its ISDN interfaces. The snapshot server
command specifies the length of the active period and whether the
router is allowed to dial remote sites to exchange routing updates
in the absence of regular traffic.
The remote routers are configured for
snapshot routing by applying the snapshot
client command to each ISDN
interface. The snapshot
client interface
configuration command specifies the following variables:
- The length of the active period
(which must match the length specified on the central router)
- The length of the quiet period
- Whether the router can dial the
central router to exchange routing updates in the absence of
regular traffic
- Whether connections that are
established to exchange user data can be used to exchange
routing updates
Examine the configuration of the
Central Router. The snapshot
server interface
configuration command enables snapshot routing. The "5"
sets the length of the active period to five minutes.
Examine the configuration of the Home
Router. The dialer map
snapshot interface
configuration command establishes a map (whose sequence number is 1)
that the router uses to connect to the central site router for the
exchange of routing updates. The name
keyword specifies the name of the remote router that is associated
with the dial string. Because the ppp
authentication interface
configuration command enables CHAP authentication, when this router
dials the central router, it receives the host name of the central
router and compares it with the name specified by the name
keyword.
The snapshot
client interface
configuration command sets the length of the active period to five
minutes (a value that must match the value set in the snapshot
server's configuration) and sets the length of the quiet period to
43,200 seconds (12 hours). The suppress-statechange-updates
keyword prevents the routers
from exchanging updates during connections that are established to
transfer user data. The dialer
keyword allows the client router to dial up the server router in the
absence of regular traffic and is required when you use the suppress-statechange-update
keyword.
When the backbone routing protocol is
not supported by snapshot routing (for example, OSPF or EIGRP),
standard routing redistribution techniques can be used to ensure
that routing updates are propagated between routing protocols, as
required. Care should be taken to ensure redistribution of subnets
if needed and to avoid routing loops.
 |
 |
Lab
Activity |
| |
The
Phoenix and Denver offices want to exchange
routing updates without incurring large
telecommunication bills. Your solution is to
configure snapshot routing between the two
routers. |
|
|
|
|