Users Guide

Implementation Information...................................................................................................................................... 136
Logging of ACL Processes.............................................................................................................................................. 137
Guidelines for Conguring ACL Logging.................................................................................................................... 137
Conguring ACL Logging.......................................................................................................................................... 138
Flow-Based Monitoring Support for ACLs.......................................................................................................................138
Behavior of Flow-Based Monitoring..........................................................................................................................139
Enabling Flow-Based Monitoring...............................................................................................................................140
9 Bidirectional Forwarding Detection (BFD)....................................................................142
How BFD Works............................................................................................................................................................. 142
BFD Packet Format.................................................................................................................................................. 143
BFD Sessions............................................................................................................................................................144
BFD Three-Way Handshake......................................................................................................................................145
Session State Changes............................................................................................................................................. 147
Important Points to Remember.......................................................................................................................................147
Congure BFD................................................................................................................................................................ 147
Congure BFD for Physical Ports..............................................................................................................................148
Congure BFD for Static Routes............................................................................................................................... 151
Congure BFD for OSPF.......................................................................................................................................... 152
Congure BFD for OSPFv3.......................................................................................................................................154
Congure BFD for IS-IS............................................................................................................................................ 156
Congure BFD for BGP............................................................................................................................................ 158
Congure BFD for VRRP.......................................................................................................................................... 164
Conguring Protocol Liveness...................................................................................................................................167
Troubleshooting BFD.................................................................................................................................................167
10 Border Gateway Protocol IPv4 (BGPv4).................................................................... 169
Autonomous Systems (AS).............................................................................................................................................169
Sessions and Peers..........................................................................................................................................................171
Establish a Session.....................................................................................................................................................171
Route Reectors............................................................................................................................................................. 172
BGP Attributes................................................................................................................................................................173
Best Path Selection Criteria...................................................................................................................................... 173
Weight...................................................................................................................................................................... 175
Local Preference.......................................................................................................................................................175
Multi-Exit Discriminators (MEDs)..............................................................................................................................176
Origin........................................................................................................................................................................ 177
AS Path.....................................................................................................................................................................177
Next Hop.................................................................................................................................................................. 178
Multiprotocol BGP...........................................................................................................................................................178
Implement BGP with Dell Networking OS....................................................................................................................... 179
Additional Path (Add-Path) Support......................................................................................................................... 179
Advertise IGP Cost as MED for Redistributed Routes...............................................................................................179
Ignore Router-ID in Best-Path Calculation.................................................................................................................180
Four-Byte AS Numbers.............................................................................................................................................180
AS4 Number Representation.................................................................................................................................... 180
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