Users Guide

Logging of ACL Processes.............................................................................................................................................. 138
Guidelines for Conguring ACL Logging....................................................................................................................139
Conguring ACL Logging.......................................................................................................................................... 140
Flow-Based Monitoring Support for ACLs...................................................................................................................... 140
Behavior of Flow-Based Monitoring...........................................................................................................................141
Enabling Flow-Based Monitoring...............................................................................................................................142
9 Bidirectional Forwarding Detection (BFD)....................................................................144
How BFD Works............................................................................................................................................................. 144
BFD Packet Format.................................................................................................................................................. 145
BFD Sessions............................................................................................................................................................146
BFD Three-Way Handshake...................................................................................................................................... 147
Session State Changes............................................................................................................................................. 149
Important Points to Remember.......................................................................................................................................149
Congure BFD................................................................................................................................................................ 149
Congure BFD for Physical Ports............................................................................................................................. 150
Congure BFD for Static Routes...............................................................................................................................153
Congure BFD for OSPF.......................................................................................................................................... 154
Congure BFD for OSPFv3.......................................................................................................................................157
Congure BFD for IS-IS............................................................................................................................................ 158
Congure BFD for BGP............................................................................................................................................ 160
Congure BFD for VRRP.......................................................................................................................................... 167
Conguring Protocol Liveness.................................................................................................................................. 169
Troubleshooting BFD.................................................................................................................................................169
10 Border Gateway Protocol IPv4 (BGPv4)..................................................................... 171
Autonomous Systems (AS)..............................................................................................................................................171
Sessions and Peers......................................................................................................................................................... 173
Establish a Session....................................................................................................................................................173
Route Reectors............................................................................................................................................................. 174
BGP Attributes................................................................................................................................................................175
Best Path Selection Criteria...................................................................................................................................... 175
Weight.......................................................................................................................................................................177
Local Preference....................................................................................................................................................... 177
Multi-Exit Discriminators (MEDs)..............................................................................................................................178
Origin........................................................................................................................................................................ 179
AS Path.....................................................................................................................................................................179
Next Hop..................................................................................................................................................................180
Multiprotocol BGP.......................................................................................................................................................... 180
Implement BGP with Dell Networking OS........................................................................................................................181
Additional Path (Add-Path) Support.......................................................................................................................... 181
Advertise IGP Cost as MED for Redistributed Routes............................................................................................... 181
Ignore Router-ID for Some Best-Path Calculations................................................................................................... 182
Four-Byte AS Numbers.............................................................................................................................................182
AS4 Number Representation.....................................................................................................................................182
AS Number Migration............................................................................................................................................... 184
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