IMPLEMENTATION OF VIRTUAL AGGREGATION

USING QUAGGA

Summer Internship, 2009 project done by Dushyant Arora under the

guidance of Dr. Paul Francis

At

Continuously growing address space Rapid Growth of Default Free Routing Table (DFRT).

Size of FIB (Forwarding Information Base): issue of concern.

Virtual Aggregation

Address space is partitioned into virtual prefixes.

Larger than any aggregatable prefix in use today.

Full RIB on all routers

Populate the Routing Information Base (RIB) as normal.

Changes required in the router operation are relatively minor.

VIRTUAL AGGREGATION

Dest Next Hop20.5/16 1.1.1.136.3/16 2.1.1.1. . . .

Today: All routers have routes to all destinations

Virtual Aggregation(VA): Routers have routes to only part of the address space

Virtual Prefixes

Dest Next Hop20.5/16 1.1.1.1. . . .

Dest Next Hop188.3/16 2.1.1.1. . . .

“Aggregation Point” routers for the red Virtual Prefix

Virtual Prefixes

VA can be deployed autonomously by a single ISP.

Neighbouring ISPs can run BGP without VA.

Paths through the ISP have two components:

1: Ingress router tunnels packets to the appropriate APR(Aggregation Point Router).

2: The virtual prefixes are aggregated at the APR.

3: APR tunnels packets to remote ASBR (Autonomous System Border Router) through Egress Router.

When advertising NLRI reachable through 2.2.2.2, local ASBR wouldadvertise a BGP NEXT_HOP of 10.1.1.1 instead of 2.2.2.2. Packets received at the tunnel endpoint 10.1.1.1 would be forwarded to 2.2.2.2 after detunneling.

Create virtual interfaces for the new next-hops. These new virtual interfaces are advertised via OSPF to all routers within the AS.

Quagga Quagga is an open source routing software based on the Zebra

router.

Supports RIP, OSPF and BGP protocols.

Composed of several daemons, one per routing protocol.

Each daemon has its own configuration file and terminal.

IMPLEMENTATION

IMPLEMENTATIONThe following commands were installed inside Quagga source code for implementing VA -

1) enable popular prefix2) read vp list3) apr id A.B.C.D4) apr vp A.B.C.D/M5) enable virtual aggregation6) change next-hop A.B.C.D A.B.C.D7) remove vp A.B.C.D/M8) remove popular prefix A.B.C.D/M

9) show vplist10) show popular prefix 11) show sub prefix12) show tunnel summary13) show apr summary

VP List - VA routers must be able to distinguish VP's from sub-prefixes. List of VPs known as VP-list is statically configured into all VA routers.

Popular Prefix - These prefixes can be directly installed in the FIBs. Stored in a list statically configured into the VA Routers.

Routers are configured so that they do not advertise VPs to remote ASBR.

We can add/remove VP's and PP's while the router is running.

Tunnel reutilization & garbage collection has also been implemented.

CONFIGURATION TESTBED

Odin Cluster

Questions

Prepared ByDushyant Arora