Using 802.1Qaw to achieve Loopback in PBB-TE environment

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Using 802.1Qaw to achieve Loopback in PBB-TE environment Powered By Docstoc
					PBB-TE 1:1 Protection
 with Load Sharing

 Ben Mack-Crane (tmackcrane@huawei.com)
    Linda Dunbar (ldunbar@huawei.com)
     Bob Sultan (bsultan@huawei.com)
ZhuSheng Deng (dengzhusheng@huawei.com)
      1:1 Protection w/ Load Sharing

•   1:1 Protection
    – Protection Group
        • Working and Protect entities
    – Faults (W-SF, P-SF)
    – Admin Requests (LO, FS, MS)
•   Load Sharing Impact
    – Traffic is distributed (BSIs mapped to TESIs)
        • all TESIs in Protection Group may be Working for some BSIs
        • for each Working TESI the rest may be Protecting
    – Faults identified by TESI (not by role)
    – Admin Requests by TESI (not by role)
        • LO: remove traffic from TESI (FS == LO-W)
        • MS: remove traffic from TESI if no faults present
    – Model allows Protection Group with more than two TESIs
                      Load Sharing



                          BEB-A

            CBP
   I-LAN




                  TESIs


                                                         BEB-A

                                          CBP




                                  I-LAN
Working load is shared                          TESIs

                                                X       Failed TESI




                            Protection load is shared
                         Traffic Engineering


Traffic between edge bridges can be distributed to multiple routes
   – control link loading
   – make efficient use of available resources

                   BCB                      BCB     BEB-C




       BEB-A                    BCB




                   BCB                      BCB     BEB-B




                                BCB
                         Parallel Links


Traffic distribution can be engineered across parallel links
   – more deterministic than Link Aggregation hashing




     BEB-A         BCB            BCB          BCB             BEB-C
        Conventional 1:1 Protection is a Subcase
                              BCB                  BCB         BEB-C




                  BEB-A              BCB




                              BCB                  BCB         BEB-B




                                     BCB




                             BEB-A                                      BEB-A
            CBP
                                                         CBP
I-LAN




                                           I-LAN




                     TESIs
                                                               TESIs

                                                               X       Failed TESI
         Bandwidth Analysis (LS vs. Non-LS)


Capacity B required between each pair of BEBs
Each link can carry N TESIs of bandwidth B
Each protection group has S TESIs (LS) or 2 TESIs (non-LS)
Assume Roughly Even BSI Distribution
                    Bandwidth Calculation


•   Variables
    – S: The number of TESIs between a pair of BEBs (LS)
    – B: The total working bandwidth reserved between two BEBs
    – N: The number of TESIs sharing a link
•   Load Sharing
    – Link carries bandwidth load of (NB/S)*(1+(1/(S-1)))
•   Non Load Sharing
    – Link carries bandwidth load of B*CEILING(2N/S)
•   Ratio of Non Load Sharing to Load Sharing
    – B*CEILING(2N/S) / ((NB/S)*(1+(1/(S-1))))
    – CEILING(2N/S) / ((N/S)*(1+(1/(S-1))))
    – (S(CEILING(2N/S))) / (N(1+(1/(S-1))))
                               Bandwidth Gain


•   Ratio of NLS to LS minus 1 (as a percent)
     – (((S(CEILING(2N/S))) / (N(1+(1/(S-1)))) - 1)*100
     – 0% means no advantage for load sharing (e.g., LS with two TESIs)

                                                           200%




                                                           100%
                                                              Bandwidth
                                                                Gain
                            10
             Number of TESIs 15
             Traversing Link
                               20                        0%
                                        4    6    8    10
                                    2
                                         Number of TESIs
                                        between BEB Pair

				
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posted:4/19/2014
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