Presentation on theme: "Ben Mack-Crane 9-Feb-141. bp-sajassi-cfm-0711-v01.pdf Flow-Level CFM: CFM functions performed on the user flows. Network-Level CFM: CFM functions performed."— Presentation transcript:
Ben Mack-Crane 9-Feb-141
bp-sajassi-cfm-0711-v01.pdf Flow-Level CFM: CFM functions performed on the user flows. Network-Level CFM: CFM functions performed on a test VLAN that covers the network. Test flows are chosen to exercise all ECMPs for the Test VLAN. Service-Level CFM: CFM functions performed on a service VLAN. Test flows are chosen to exercise all ECMPs for that VLAN. It can be considered as a special case of NetworkLevel CFM. 9-Feb-142
Test Flow Discovery Computed set of (SA, DA, Flow Hash) for Network or Service Path Trace Link Trace Path Verification Loopback Fault monitoring CCM, infer Flow Hash from RDI Fault Isolation Loopback DDCFM 9-Feb-144
LTM sent to individual DA with specific Flow Hash Each hop sends back LTR (if LTM TTL is not 0) Forwards LTM to ECMP selected hop (if LTM TTL is >1) LTR frames identify path for DA+Flow Hash 9-Feb-145 LTM to individual address w/ flow hash LTR may take any path
LBMs sent to individual DA with Flow Hash to select path LBM MIP TLV contains MIP address MIP responds with LBR LBR may take different path from LBM Could add Flow Hash TLV to LBM to attempt to make LBR symmetric… But there is no guarantee that LBR is symmetric if network is misbehaving! 9-Feb-146 LBM to Individual DA, MIP address in TLV LBR to LBM SA
CCMs sent from B-VLAN endpoint (CBP) use a source specific tree* Each endpoint expects to receive CCMs from all other endpoints Detects unreachable endpoint Does not test all paths 9-Feb-147 CCM to Group Address Cs-ss-ss FF * Or a shared tree using group address 80-1E FF
CCMs sent from a CBP MEP within a TESI mux (specific to VID, SA, DA) using a specific Flow Hash Multiple paths can be tested using a list of Flow Hash values, each sent at least three consecutive times Detects broken path (but not rerouted path) 9-Feb-148 CCM to Individual Address* Flow Hash A Flow Hash B Flow Hash C *Option to use flow-specific group address?
MEP location in baggy pant leg Support for Flow Filtering shim with 6.11 (or 6.9) MEP/MIP locations unchanged Use TESI mux (6.19) for path test MEPs PNP only supports ECMP MIPs Partial paths ECMP VLAN are not interesting 9-Feb-149
10 Placing Flow Filtering shim with CBP shim: -Keeps all tag processing together CFM : -MEP generates CCM frames with group address for default I-SID.
9-Feb-1411 Placing Flow Filtering shim with CBP shim: -Keeps all tag processing together CFM : -MEP generates CCM frames with individual address -Flow Hash value(s) selected to test desired path(s)
9-Feb-1412 Placing Flow Filtering shim with VLAN tag shim: -Keeps all tag processing together -Could have used one tag to carry all info Only MIPs supported on PNP for ECMP VLANs -ECMP makes MEPs less useful here
Path verification Determine expected path via computation or LTM Use Loopback to verify each hop in path Fault isolation Use Loopback to find broken hop DDCFM supports special diagnostics, i.e. reflecting specific frames or injecting test frames 9-Feb-1413