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Deutsche TelekomTechnical Engineering Center. Fat PW Loadbalancing.

http://www.ietf.org/internet-drafts/draft-bryant-filsfils-fat-pw-00.txtAuthors:- Stewart Bryant, Cisco Systems- Clarence Filsfils, Cisco Systems- Ulrich Drafz, T-Com- Wilfried Maas, T-Systems- Joerg Kuechemann, T-Com Fat PW Loadbalancing.

Fat PW Loadbalancing.Outline • Problem Statement • Solution Space • Deep Packet Inspection • Loadbalancing Label • PW Label Range • Changes • Conclusion

2.5 GBit/sec 2.5 GBit/sec 1GBit/sec 1GBit/sec 2.5 GBit/sec 2.5 GBit/sec Fat PW Loadbalancing.Problem Statement Data Flow • Customers Traffic bound to PW Label 4242 3 • Transport Label is chosen by Hash Algorithm 51 4242 44 • Result of Hash Algorithm will be always the same 3 Thus Pseudo Wires may lead to undesirable asymetric load Hash = F{Loopback, PW-Label}

Fat PW Loadbalancing.Deep Packet Inspection • DPI with PW is a difficult thing to do - if at all possible • The ´0000´ in first nibble does not mean IP so P routers have no clue what to make of the packet • And if it was possible it would need a huge amount of computation power at all participating P and PE devices

2.5 GBit/sec 2.5 GBit/sec 1GBit/sec 1GBit/sec 2.5 GBit/sec 2.5 GBit/sec Fat PW Loadbalancing.PW Label Range Traffic • Customers Traffic bound to PW Label (4242...4243) which needs to be chosen at the Edge 3 • Transport Label is chosen by Hash Algorithm 51 4243 4242 44 • Result of Hash Algorithm will be a Function of chosen PW-Label 3 In Real World Implementations a Label Range of 8 – 16 Labels might be enough Hash = F{Loopback, PW-Label}

Fat PW Loadbalancing.PW Label Range CE Ethernet IP (Payload) VPWSVPLS Primary Hash PE Traffic Hash L2Eth/Pos MPLS LDP MPLS PW Ethernet IP (Payload) Multiple Pseudwire Labels (Range needs to be defined) P MPLS-PHP Pop of LDP Label L2Eth/Pos MPLS PW Ethernet IP (Payload) Hash VPWSVPLS PE Ethernet IP (Payload) CE

2.5 GBit/sec 2.5 GBit/sec 1GBit/sec 1GBit/sec 2.5 GBit/sec 2.5 GBit/sec Fat PW Loadbalancing.Load Balancing Label Data Flow • Customers Traffic bound to PW Label 4242 3 51 • LB Labelis chosen out of2^20for each flow identified by the Edge Device PW:4242 LB:2022 • Result of Hash Algorithm will be a Function of PW-Label and LB Label 44 PW:4242 LB:1566 3 In Real World Implementations a LB Label Space of smaller then 2^20 might still be good enough ;-) Hash = F{Loopback, LB Label, PW-Label}

Fat PW Loadbalancing.Load Balancing Label CE Ethernet IP (Payload) VPWSVPLS Hash (primary) Traffic PE Hash L2Eth/Pos MPLS LDP MPLS PW Ethernet MPLS LB Label IP (Payload) multiple LB Labels (potentially 2^20) P MPLS-PHP Pop of LDP Label L2Eth/Pos MPLS PW MPLS LB Label Ethernet IP (Payload) Hash VPWSVPLS PE Ethernet IP (Payload) CE

Fat PW Loadbalancing.Needed Changes • New TLVs for Pseudowire signaling • Label Block TLV (definition of Label Block) • LB Label TLV (LB Label is present) • Per hop behavior needs only be changed at PEs • PWE Signaling • Forwarding (ingress and egress)

Fat PW Loadbalancing.Conclusion • We feel that we have a problem and need to get at least one solution • So far as we can see there are two feasible solutions: • Label Range Solution • Probably easy to implement and good enough to solve the current problem • Changes only needed at the Edge • Load Balancing Label • More generic solution and therefore the better one • Changes only needed at the Edge

Fat PW Loadbalancing.Further Steps • Both approaches do not interwork with each other • Shall we persue both in the same draft? • Shall we persue both in different drafts? • Shall we choose one? • Our preference would be the Load Balancing Label but for the sake of backward compatibility we would be content with Label Block as well

Thank you for your attention!

Backup

LDP 60 LDP 50 LDP 60 LDP 50 PW 30 PW 30 LDP 50 LDP 60 LDP 51 LDP 61 LDP 51 LDP 61 L2 ECMP for Pseudo Wire based ServicesProblem and Solution CE B=Routerwithout L2 Flow detection for ECMP CE PE-1 PE-1 A=Router with L2 Flow detection for ECMP VPWSVPLSService B VPWSVPLSService A Traffic can only use one path through the Network P P P P In the Future the traffic should se all ECMP paths through the network P P P P PHP No LDP Label PHP No LDP Label PW 30 Traffic Traffic CE VPWSVPLSService PE-2 CE VPWSVPLSService PE-2 Label binding Label binding B A Pseudovire path Pseudovire and Flow Label(s) Transport Label LDP 60

L2-ECMP ProposalFilter and Hash definition for VPLS/VPWS (simple use case) • Filtering and hashing function must become part of the VPWS/VPLS application at the PE. At the VPLS ingress PE all traffic is Ethernet traffic. • Number of VLAN Headers could be 0, 1 or 2 • Filtering should only be don on IP-Version: 4 Protocol is IPv4 • Hashing must be done on the IP-Address in the VPLS/VPWS Payload

L2-ECMP ProposalFilter and Hash definition for VPLS/VPWS (complex use case) • Filtering and hashing function must become part of the VPWS/VPLS application at the PE. At the VPLS ingress PE all traffic is Ethernet traffic. • Number of VLAN Headers could be 0, 1 or 2 • MPLS (Carriers Carrier) with up to two labels could be present • Filtering should only be don on IP-Version: 4 Protocol is IPv4 • Hashing must be done on the IP-Address in the VPLS/VPWS Payload

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