Re: [RRG] Topology that follows addressing

In einer eMail vom 27.11.2007 20:54:53 Westeuropäische Normalzeit schreibt tli@cisco.com:

I'm pretty sure I don't understand that explanation.

Advertising all of ISP A's prefix isn't the issue at all. The real question is: what happens at the geo-patch abstraction (action) boundary? Where is that boundary?

I think I have explained this: At the event that an IP packet shall be forwarded, the first (like the following) inside some geopatch realizes that its own as well as the packet's destination have the same longitude/latitude and therefore the next hop is determined based on the recognized destination node which has a best suitable reachability info.

And I think I have explained the routing protocol. Maybe I should write more about the recursion.

Who is responsible for traffic arriving into the geo-patch?

the receiving node, who else ? but maybe I do not understand the question.

What happens if the topology within the geo-patch is internally disconnected?

Permanent partition ( I placed just a few line to show that I am aware of this problem which is certainly for further study). Maybe it should be requested that at least one representative node must also show up in the next higher level map. Then any node of one particular partition will learn via the next upper level map that there are more such representative nodes than disposed/contributed by this partition. Hence the partition is detected. I am sure that there are several ways to treat this problem (partition id?, partition bridging area,...

I am optimistic. When we started PNNI we had much less available.

The traditional explanation is that there must be regulations requiring an interconnect for the geo-patch and all providers must connect to that interconnect. The alternative is that providers with links outside of the geo-patch end up receiving traffic destined for other providers and end up providing free transit.

COMMENT: At first it takes knowledge about shortest path routing. Then we can come up with provider constraints and assign QOS/policy attributes to the loose links.

More generally, if the entry point at an abstraction action boundary is not directly connected to all of the sub-abstractions, then you have a situation where traffic must traverse a sub-abstraction, which will violate commercial constraints. Thus, the abstraction action boundary must be located where there is common (or free) connectivity to all of the sub-abstractions. You can conceivably shift the abstraction action boundary away from the abstraction naming boundary to help with this (i.e., do proxy aggregation), but how is this maintained in the face of changing topology and across hierarchical levels?

I am not sure I understand your questions. Maybe I should write more about the adjacency of two different nxm-square-degree geo-patches.

Maybe this helps to avoid wrong understanding: In the past Germany conquered parts of France, and vice versa France conquered parts of Germany. But that did not change the shortest path between Paris and Berlin at all.

The OSPF assumption that all routers are willing to carry all traffic simply doesn't hold in the inter-domain routing arena.

See COMMENT above. I assume, EBGP hops only won't deliver the packet either, will they? Honestly, if you have a viewed topology (nicely sparsed to become scalable), you can do better policies and TE than by just having AS-path strings, right?

Heiner