1. doc.: IEEE 802.11-04/0980r0 Routing and Forwarding Separation August 27, 2004 Tricci So – Nortel Networks Slide 1 Routing and Forwarding Separation Separation Prepared by Tricci So Nortel Networks

2. doc.: IEEE 802.11-04/0980r0 Routing and Forwarding Separation August 27, 2004 Tricci So – Nortel Networks Slide 2 ObjectivesObjectives  Describes the differences between routing and forwarding  Describes the benefits of separating the routing process from the forwarding process  Recommendations to TGs

3. doc.: IEEE 802.11-04/0980r0 Routing and Forwarding Separation August 27, 2004 Tricci So – Nortel Networks Slide 3 What is Routing?  The process of determining what usable path(s) (or what usable “route(s)”) that frames may take from source to destination  Information is compiled into a “routing table”, which maps the required destination to one or more egress interface(s)  Routing table either created manually (i.e. “statically”) or by using a routing protocol (i.e. “dynamically”) and shall be maintained to reflect the latest network topology  Routing is the process to establish the routing table (network topology) through the support of routing protocol(s), routing algorithm(s) and metric(s), the routing topology information will then be converted to the forwarding table to support the forwarding process  One or more routing protocols can be used to build the routing table Network IDNext HopCost 13309:00:1a:b2:c0:e1 Example of Routing Table

4. doc.: IEEE 802.11-04/0980r0 Routing and Forwarding Separation August 27, 2004 Tricci So – Nortel Networks Slide 4 What is Forwarding?  The process of examining addressing information in a newly arrived frame and then sending it (or “forwarding” it) along the path that was determined by the routing process.  Forwarding is accomplished by looking up the forwarding table and then based on the addressing information, deciding on which egress interface to send the frame.  Forwarding examples:  Forwarding “unicast” frame via “destination” address matching in the unicast forwarding table  Forwarding “multicast” frame via “source + destination” addresses matching and incoming interface filtering in the multicast forwarding table Network IDDest. AddrNext Hop I/F Addr. 1309:00:1a:b2:c0:e1 Example of Forwarding Table 08:01:36:a4:9b:f2

5. doc.: IEEE 802.11-04/0980r0 Routing and Forwarding Separation August 27, 2004 Tricci So – Nortel Networks Slide 5 Separate Routing & Forwarding Processing Control Path Processing Routing / Signaling Network/Routing Topology Processing Routing Algorithm & Metric FrameScheduler RoutingTable NetworkPolicies Classifier Data Path Processing Data Path Processing & Frame Forwarding Lookup ForwardingTable Routing & Forwarding Separation Advantages:  decouple the forwarding processing from routing processing  minimize impact of routing processing on forwarding performance  allow the independent routing and forwarding design evolution Routing & Forwarding Separation Advantages:  decouple the forwarding processing from routing processing  minimize impact of routing processing on forwarding performance  allow the independent routing and forwarding design evolution

6. doc.: IEEE 802.11-04/0980r0 Routing and Forwarding Separation August 27, 2004 Tricci So – Nortel Networks Slide 6 RecommendationsRecommendations  TGs should take the approach of designing the system architecture by separating the routing from forwarding processing to enable better system performance and evolvable network solutions.  Define a generic protocols and forwarding mechanism that can support different routing protocols that support various ESS Mesh network deployment scenarios.  TGs should take the approach of designing the system architecture by separating the routing from forwarding processing to enable better system performance and evolvable network solutions.  Define a generic protocols and forwarding mechanism that can support different routing protocols that support various ESS Mesh network deployment scenarios.