IETF 63 Paris L 2 VPN WG LDP
- Slides: 8
IETF 63 Paris L 2 VPN WG LDP Autodiscovery LDP-based Autodiscovery draft-stein-ldp-auto-00. txt joint work with Simon Delord 1
Access Network Architecture CE CE fiber access node CE P CORE PE (S-PE) P CE CE P P P D S L A M CE CE P P MPLS-enabled Access Network there may also be combined multiservice access nodes Core Network 2
Access Network Characteristics ACCESS NETWORK CORE NETWORK simple tree (or ring) topology rich topology (may be redundant links) limited BW huge BW limited computational power strong computational power 1000 s of access nodes smaller number of routers no BGP, may not be IGP BGP LDP for access LSP setup LDP 3
MS-VPLS CE CE access network CE CE CE S P E CE CE core C CE CE access network S P E core A access network CE core B CE S P E CE CE CE MS-VPLS supported by MS-PWs access network CE CE CE PE in Vset PE joining Vset PE not in Vset 4
Service Discovery network elements and links (in both access and core networks) are relatively static (perhaps add or change 1 or 2 elements per day) hence network discovery is not an operational burden manual provisioning of LDP sessions between PEs is reasonable services are by their nature dynamic (perhaps add several users per day to each set of services) manual provisioning of services is a logistical nightmare for scalability need service discovery when BGP is available (i. e. in core network) it can be used for autodiscovery of all types when only LDP is available need to have an LDP-based technique 5
Autodiscovery possibilities n central server holding Vset (single point of failure) n each PE in Vset periodically advertises the fact (very chatty) n PW wanting to join Vset sends label mapping to all PEs (thousands of un-necessary mapping messages and perhaps bindings) n PE wanting to join Vset inquires and initiates PW setup (w/o central server needs to send inquiry messages and collect responses and then one PE needs to initiate setup of many MS-PWs) n PE wanting to join Vset announces (join messages) and Vset members initiate PW setup 6
JOIN Message CE CE S P E CE CE CE core B S P E CE core A CE CE S P E CE CE CE core C CE CE CE S P E CE CE CE S P E CE CE NB SPE used for JOIN message is not necessarily used by PW CE 7
PW Setup CE CE S P E CE CE CE S P E core B S P E CE CE CE core C CE CE CE core A CE CE S P E CE CE CE PW setup uses whatever MS-PW mechanism PWE 3 decides upon 8
