Itu telecommunication Standardization Sector Temporary Document xxx(plen) study group 15


III.2.4 External Routers running OSPF or other IP Routing Protocols



Download 0.91 Mb.
Page17/20
Date05.05.2018
Size0.91 Mb.
#48203
1   ...   12   13   14   15   16   17   18   19   20

III.2.4 External Routers running OSPF or other IP Routing Protocols


Many operators currently run level-2 IS-IS in their external routers, and OSPF or other routing protocols for IP. In this case the external router must remain as the level-2 router for the SDH NEs, and so for a dual area must be a dual Integrated IS-IS router. However the router may be configured to route all IP packets using OSPF by configuring redistribution of IP routes between IS-IS and OSPF. In this way all IP packets will be OSPF routed, whilst CLNP packets continue to be level-2 IS-IS routed. This is shown in Figure III-4.



Figure III-4

Note that the Integrated IS-IS stack in the external routers will not be aware that the level-2 subdomain is meant only for CLNP packets. The OSPF learned routes must therefore be redistributed into Integrated IS-IS with a low default metric, to make them more attractive to IP packets than the level-2 sub-domain.




Download 0.91 Mb.

Share with your friends:
1   ...   12   13   14   15   16   17   18   19   20




The database is protected by copyright ©ininet.org 2024
send message

    Main page