AIS AI2524 Configure Variations of the Static Route, Map Nsap Addresses to Media Addresses

Chapter 9: AI2524 OSI/CLNP Configuration Steps

5.Pass packets bound for sid in dom ain47.0006.0200 through serial 0:

clns route 47.0006.0200 sid

CLNS routing updates will not be sent on the serial link; however,

CLNS packets will be sent and received over the serial link.

Configure Variations of the Static Route

These tasks include variations of the clns route global configura- tion command:

zBind the next hop to a specified interface and media address when you do not know the NSAP address of your neighbor. Note that this version of the clns route command is not literally applied to a specific interface.

clns route nsap-prefix type number [snpa- address]

zTell the Cisco IOS software to discard packets with the specified NSAP prefix.

clns route nsap-prefixdiscard

zSpecify a default prefix.

clns route default nsap-prefix type number

Map NSAP Addresses to Media Addresses

Conceptually, each ES lives in one area. It discovers the nearest IS by listening to ES-IS packets. Each ES must be able to communicate di rectly with an IS in its area.

When an ES wants to communicate with another ES, it sends the packet to any IS on the same medium. The IS looks up the destination NSAP address and forwards the packet along the best route. If the des- tination NSAP address is for an ES in another area, the Level1 IS sends the packet to the nearest Lev el2 IS. The Lev el2 IS forwards the packet along the best path for the destination area until it gets to a Level 2 IS that is in the destination area. This IS then forwards the packet along the best path inside the area until it is delivered to the des- tination ES.

ESs need to know how to get to	a Level1 IS for their area, a nd Level1
ISs need to know all of the ESs that are directly reachable through each
of their interfaces. To provide this information, the routers support the
August 1997	Page 9-41
2524UM