1. www.huawei.com Hierarchical Routing Architecture Introduction draft-xu-rrg-hra-00.txt Routing Research Group Xiaohu XU (xuxh@huawei.com)xuxh@huawei.com Sheng JIANG (shengjiang@huawei.com)shengjiang@huawei.com

2. Page 2/11Content  Background  Hierarchical Routing Architecture  HRA Overview  Hierarchical Routing Mechanism  Hierarchical Host Identifier Tag  ID/Locator Mapping System  Benefits  Future Work and Open Issues

3. Page 3/11 Background Routing growth threats Routing growth threats More CPU, More TCAM More CPU, More TCAM More power consumption More power consumption CapEx and OpEx rise CapEx and OpEx rise Main causes: Main causes: Multi-homing Multi-homing Traffic-engineering Traffic-engineering PI address PI address

4. Page 4/11 Background Underlying reason for routing growth Underlying reason for routing growth Dual role of IP address Dual role of IP address ID/Locator split is a basic idea to solve this issue ID/Locator split is a basic idea to solve this issue Virtual ID between communication entities, eg. shim6 Virtual ID between communication entities, eg. shim6 Crypto host ID, eg.HIP Crypto host ID, eg.HIP EID/RLOC split, eg.LISP EID/RLOC split, eg.LISP EID/AS split, eg.ENCAPS, HLP EID/AS split, eg.ENCAPS, HLP Locator Identifier

5. Page 5/11 Hierarchical Routing Architecture Overview One of ID/Locator split solutions One of ID/Locator split solutions Hierarchical routing mechanism Hierarchical routing mechanism Independent Locator Domain (LD), Each locator domain has a global unique LDID Independent Locator Domain (LD), Each locator domain has a global unique LDID Support multiple independent address spaces Support multiple independent address spaces A combination of LDID and local locator is a global unique locator A combination of LDID and local locator is a global unique locator Hierarchical Host Identifier Tag Hierarchical Host Identifier Tag A combination of a management domain ID and a hash value of Host Identifier (public key) A combination of a management domain ID and a hash value of Host Identifier (public key) Hierarchical mapping system Hierarchical mapping system Mapping services between Host Identifier Tags and locators Mapping services between Host Identifier Tags and locators Using HIT as the lookup key Using HIT as the lookup key

6. Page 6/11 LD 5 LD 3 LD 1 LD 4 LD 2 R1 R3 R2 R5 R4 R7 R6 Hierarchical Routing Mechanism 2-level hierarchical routing 2-level hierarchical routing Inter-LD routing and intra-LD routing Inter-LD routing and intra-LD routing Locator Domain Border Routers (LDBRs) exchange LD reachability information Locator Domain Border Routers (LDBRs) exchange LD reachability information LDBRs only store LD-ID based routing information LDBRs only store LD-ID based routing information Internal routers support prefix-based routing Internal routers support prefix-based routing Internal routers only store internal routing information Internal routers only store internal routing information

7. Page 7/11 LD 3 Example1: Routing within the same LD APP HIT B LD 3 + IPv4 B Src.IPv4 A Dst.IPv4 B LD 5 LD 1 LD 4 LD 2 R1 R3 R2 R5 R4 R7 R6 Host A Host B APP HIT A LD 3 + IPv4 A LD ID + local locator = global unique locator IPv4 Routing Payload HIT A -> HIT B (LD3+IPv4 A) -> (LD3+IPv4 B)

8. Page 8/11 Example2: Routing between different LDs LD 5 LD 3 LD 1 LD 4 LD 2 R1 R2 R5 R4 R7 R6 LD ID + local locator = global unique locator Host A APP HIT A LD 3 + IPv4 A Host B APP HIT B LD 4 + IPv6 B Src.IPv6 R3 Dst.IPv6 R2 Src.IPv6 R2 Dst.IPv6 B Src.IPv4 A Dst.IPv4 R1 Src.IPv4 R1 Dst.IPv4 R3 R3 Payload HIT A -> HIT B (LD3+IPv4 A) -> (LD4+IPv6 B) Payload HIT A -> HIT B (LD3+IPv4 A) -> (LD4+IPv6 B) Payload HIT A -> HIT B (LD3+IPv4 A) -> (LD4+IPv6 B) Payload HIT A -> HIT B (LD3+IPv4 A) - > (LD4+IPv6 B) Host B HIT LD4+IPv6 B

9. Page 9/11 Host Identifier Tag Flat Host Identifier Tag Flat Host Identifier Tag Used in HIP and Node ID Architecture Used in HIP and Node ID Architecture Has scalability issues Has scalability issues Hard to manage Hard to manage No guarantee for global uniqueness No guarantee for global uniqueness Low-efficient lookup Low-efficient lookup Hierarchical Host Identifier Tag Hierarchical Host Identifier Tag A combination of a Management Domain ID (MDID) and a hash value of HI A combination of a Management Domain ID (MDID) and a hash value of HI Ease of management Ease of management Feasible and deployable mapping system with high lookup efficiency Feasible and deployable mapping system with high lookup efficiency

10. Page 10/11 ID/Locator Mapping System Hierarchical mapping system Hierarchical mapping system Each Management Domain (which may be covered several Locator Domain) has at least one local mapping server Each Management Domain (which may be covered several Locator Domain) has at least one local mapping server Each server stores local HIT->Locator mapping info Each server stores local HIT->Locator mapping info Servers store MDID->Remote LDID mapping Servers store MDID->Remote LDID mapping Lookup requests for the same MDID, can find in the local database Lookup requests for the same MDID, can find in the local database Lookup requests for different MDIDs are forwarded to Remote Locator Domain and served by its default mapping server Lookup requests for different MDIDs are forwarded to Remote Locator Domain and served by its default mapping server HIT AIPv4 A HIT BIPv4 B... LD 5 LD 3 LD 1 LD 4 LD 2 R1 R3 R2 R5 R4 R7 R6 MDID aLD2 MDID bLD5... MD b HIT B MDID b Host B HIT B (MDID b) LD 5 + IPv6 B LD5

11. Page 11/11 Benefits The routing table size in each router will be greatly reduced The routing table size in each router will be greatly reduced Routing stability will be improved Routing stability will be improved Reusable locator address space Reusable locator address space Support communication between heterogeneous networks Support communication between heterogeneous networks Management of the global HIT namespace becomes more practical Management of the global HIT namespace becomes more practical

12. Page 12/11 Future Work and Open Issues LD management issue (merge and split) LD management issue (merge and split) Routing policy Routing policy Incremental deployment Incremental deployment More details to be confirmed More details to be confirmed

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