CISCO Unknown Unicast Flooding Supperssion Software User Guide
- June 15, 2024
- Cisco
Table of Contents
Unknown Unicast Flooding Supperssion
This chapter describes how to configure unknown unicast flooding supperssion on the Cisco ASR 1000 Series Routers. This chapter contains these topics:
- About Unknown Unicast Flooding on Bridge Domain, on page 1
- Limitations for Unknown Unicast Suppression, on page 1
- Enabling Unknown Unicast Flooding on Bridge Domain, on page 1
- Feature Information for Unknown Unicast Flooding Suppression, on page 3
About Unknown Unicast Flooding on Bridge Domain
Occasionally, unknown unicast traffic is flooded to all the provider edge
device because the device does not know the destination MAC address of a
received packet. By default the unknown unicast traffic will be flooded to all
the devices. To prevent forwarding such traffic, you can configure unknown-
unicast-suppress Suppress unknown unicast flooding command.
Limitations for Unknown Unicast Suppression
If the Unknown Unicast Flooding Suppression is on, the unicast traffic towards
an unknown host will be dropped. A host becomes unknown or silent when its MAC
address ages out from the MAC address table on the PE. The PE might rely on
the Unknown Unicast Flooding to re-learn the MAC address.
Enabling Unknown Unicast Flooding on Bridge Domain
To enable unknown unicast flooding suppression, perform the following steps.
Note
By default, the unknown unicast flooding is disabled.
SUMMARY STEPS
- configure terminal
- bridge-domain {interface number}
- flooding-suppression unknown-unicast
- end
DETAILED STEPS
| Command or Action| Purpose
---|---|---
Step 1| configure terminal
Example:
Router# configure terminal| Enters global configuration mode.
Step 2| bridge-domain {interface number;
Example:
Router(config)# bridge-domain 10| 10
Configures the bridge domain on the interface.
Step 3| flooding-suppression unknown-unicast Example:
Router(config-bdomain)# flooding-suppression unknown-unicast| Enables unknown
unicast flooding suppression on the bridge domain.
Step 4| end Example:
Router(config-bdomain)# end| (Optional) Returns to privileged EXEC mode.
Verifying the Unknown Unicast Flooding Suppression
Verify that you have enabled the unknown unicst flooding suppression by
entering the following command: Device(config-bdomain)#do show run | sec
bridge bridge-domain 10 flooding-suppression unknown-unicast
This examples shows the packets that are suppressed and dropped.
Device# show pla hard qfp ac fe bridge-domain datapath 1
QFP L2BD Bridge Domain information
BD id: 1
State enabled: Yes
Aging timeout (sec) : 300
Aging active entry: Yes
Max mac limit: 65536
Unkwn mac limit flood : Yes
mac_learn_enabled: Yes
mac_learn_controled : Yes
Unknown unicast olist : Yes
otv_aed_enabled : No
otv_enabled : No
mcast_snooping_enabled : No
Feature : evpn, uuf-suppression
SISF snoop protocols : arp, ndp, dhcpv4, dhcpv6
Mac learned: 0
BDI outer vtag: 00000000
BDI inner vtag: 00000000
Replication tree info:
Global replication : depth encode 0X2000001, (head 0X29D3D000)
Split-horizon-group 0 : depth encode 00000000, (head 00000000)
Split-horizon-group 1 : depth encode 00000000, (head 00000000)
Bridge Domain statistics
| Total bridged | pkts : 0 | bytes: 0 |
|---|---|---|
| Total unknown unicast | pkts : 0 | bytes: 0 |
| Total broadcasted | pkts : 0 | bytes: 0 |
| Total to BDI | pkts : 0 | bytes: 0 |
| Total injected | pkts : 0 | bytes: 0 |
| Total mac-sec violation drop | pkts : 0 | bytes: 0 |
| Total mac-sec move drop | pkts : 0 | bytes: 0 |
| Total mac-sec unknown drop | pkts : 0 | bytes: 0 |
| Total source filter drop | pkts : 0 | bytes: 0 |
| Total bfib policy drop | pkts : 0 | bytes: 0 |
| Total replication start drop | pkts : 0 | bytes: 0 |
| Total recycle tail drop | pkts : 0 | bytes: 0 |
| Total static MAC move drop | pkts : 0 | bytes: 0 |
| Total BD disabled drop | pkts : 0 | bytes: 0 |
| Total STP state drop | pkts : 0 | bytes: 0 |
| Total UUF suppression drop | pkts : 0 | bytes: 0 |
Feature Information for Unknown Unicast Flooding Suppression
Table 1: Feature Information for Unknown Unicast Flooding Suppression
| Feature Name | Releases | Feature Information |
|---|---|---|
| Unknown Unicast Flooding Suppression | Cisco IOS XE Bengaluru 17.4 | This |
feature was introduced.
Unknown Unicast Flooding Supperssion
Documents / Resources
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CISCO Unknown Unicast Flooding Supperssion
Software
[pdf] User Guide
Unknown Unicast Flooding Supperssion Software, Unicast Flooding Supperssion
Software, Flooding Supperssion Software, Supperssion Software, Software
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