BFD between ASR9K-XR (Bundle-Ether) and ASR903 - XE (Port-channel)

rishetty · ‎06-21-2023

Problem

BFD over Port channel of ASR903 down

Solution

ASR903 Configuration of Port-channel & BFD

bfd-template single-hop AG1-ASR9K

interval microseconds min-tx 25000 min-rx 25000 multiplier 3 >> 25ms *3 timer

!

AG1-2-903#sh run int po10

Building configuration...

Current configuration : 528 bytes

!

interface Port-channel10

dampening

mtu 9202

ip address 172.27.98.220 255.255.255.254

no ip redirects

no ip unreachables

no ip proxy-arp

ip router isis CORE

ip pim sparse-mode

load-interval 30

carrier-delay up 2

carrier-delay down msec 0

ipv6 address 2405:200:13A:0:172:27:98:220/127

no ipv6 redirects

no ipv6 unreachables

ipv6 router isis CORE

mpls ip

mpls ldp igp sync delay 25

bfd template AG1-ASR9K

isis circuit-type level-1

isis network point-to-point

isis bfd

end

AG1-2-903#sh bfd neighbors interface po10 details

IPv4 Sessions

NeighAddr LD/RD RH/RS State Int

172.27.98.221 7/131077 Down Init Po10 >>>> DOWN & INIT state , ASR903 is receiving the poackets so it is in INIT state

Session Host: Hardware - session negotiated with platform adjusted timer values.

MinTxInt - configured: 25000 adjusted: 1000000

OurAddr: 172.27.98.220

Handle: 3

Local Diag: 0, Demand mode: 0, Poll bit: 0

MinTxInt: 1000000, MinRxInt: 1000000, Multiplier: 3

Received MinRxInt: 2000000, Received Multiplier: 3

Holddown (hits): 0(0), Hello (hits): 2000(0)

Rx Count: 54

Tx Count: 48

Elapsed time watermarks: 0 0 (last: 0)

Registered protocols: ISIS CEF

Template: AG1-ASR9K

Last packet: Version: 1 - Diagnostic: 3

State bit: Down - Demand bit: 0

Poll bit: 0 - Final bit: 0

C bit: 1

Multiplier: 3 - Length: 24

My Discr.: 131077 - Your Discr.: 0 >>> My Discr is matching with peer ASR9K

Min tx interval: 2000000 - Min rx interval: 2000000

Min Echo interval: 0

ASR9K

Able to ping peer IP of ASR903

RP/0/RP0/CPU0:ASR9K_1#ping 172.27.98.220

Mon Oct 25 02:50:55.096 EDT

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 172.27.98.220, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/3/6 ms

RP/0/RP0/CPU0:ASR9K_1#

RP/0/RP0/CPU0:ASR9K_1#sh bfd session interface be1601 detail

Mon Oct 25 02:51:04.918 EDT

I/f: Bundle-Ether1601, Location: 0/7/CPU0

Dest: 172.27.98.220

Src: 172.27.98.221

State: DOWN for 0d:0h:8m:58s, number of times UP: 0

Session type: SW/V4/SH/BL

Received parameters:

Version: 0, desired tx interval: 0 ms, required rx interval: 0 ms

Required echo rx interval: 0 ms, multiplier: 0, diag: None

My discr: 0, your discr: 0, H/D/F/P/C/A: 0/0/0/0/0/0

Transmitted parameters:

Version: 1, desired tx interval: 2 s, required rx interval: 2 s

Required echo rx interval: 0 ms, multiplier: 3, diag: None

My discr: 131077, your discr: 0, state DOWN, D/F/P/C/A: 0/0/0/1/0 >>>> Matching with ASR903

Timer Values:

Local negotiated async tx interval: 2 s

Remote negotiated async tx interval: 2 s

Desired echo tx interval: 0 s, local negotiated echo tx interval: 0 ms

Echo detection time: 0 ms, async detection time: 0 ms

Label:

Internal label: 506618/0x7bafa

Local Stats:

Intervals between async packets:

Tx: Number of intervals=100, min=1673 ms, max=1994 ms, avg=1827 ms >>>> Packets is getting transmitted

Last packet transmitted 1350 ms ago

Rx: Number of intervals=0, min=0 s, max=0 s, avg=0 s. >>>> No Receive

Last packet received 0 s ago

Intervals between echo packets:

Tx: Number of intervals=0, min=0 s, max=0 s, avg=0 s

Last packet transmitted 0 s ago

Rx: Number of intervals=0, min=0 s, max=0 s, avg=0 s

Last packet received 0 s ago

Latency of echo packets (time between tx and rx):

Number of packets: 0, min=0 ms, max=0 ms, avg=0 ms

MP download state: BFD_MP_DOWNLOAD_ACK

State change time: Oct 25 02:50:53.628

Session owner information:

Desired Adjusted

Client Interval Multiplier Interval Multiplier

-------------------- --------------------- ---------------------

isis-CORE 50 ms 3 2 s 3

AG1-2-903#sh ip route 10.12.0.3

Routing entry for 10.12.0.3/32

Known via "isis", distance 115, metric 30

Tag 5000, type level-1

Redistributing via isis CORE

Last update from 172.29.5.1 on TenGigabitEthernet0/3/2, 00:07:39 ago

Routing Descriptor Blocks:

* 172.29.5.1, from 10.12.0.3, 00:07:39 ago, via TenGigabitEthernet0/3/2

Route metric is 30, traffic share count is 1

Route tag 5000

Repair Path: 10.12.0.5, via MPLS-Remote-Lfa1

BFD is Down but ISIS is UP but as per RIB table above it is not using Bundle Path (So removed from RIB)

RP/0/RP0/CPU0:ASR9K_1#sh isis neighbors

Mon Oct 25 02:51:24.540 EDT

IS-IS CORE neighbors:

System Id Interface SNPA State Holdtime Type IETF-NSF

IXIA-4 BE357 *PtoP* Up 23 L1 Unable

AG1-2-903 BE1601 *PtoP* Up 28 L1 Capable

AG1-2-903#sh isis neighbors

Tag CORE:

System Id Type Interface IP Address State Holdtime Circuit Id

EAG5 L1 Te0/3/7 172.29.4.0 UP 27 00

EAG5 L1 Te0/4/5 172.29.4.2 UP 25 00

ASR9K_1 L1 Po10 172.27.98.221 UP 26 00

ASR9K-2 L1 Te0/3/2 172.29.5.1 UP 26 00

Tag RAN:

System Id Type Interface IP Address State Holdtime Circuit Id

RP/0/RP0/CPU0:ASR9K_1#sh run router isis CORE inte be1601

Mon Oct 25 02:50:17.523 EDT

router isis CORE

interface Bundle-Ether1601

circuit-type level-1

bfd minimum-interval 50

bfd multiplier 3

bfd fast-detect ipv4

point-to-point

address-family ipv4 unicast

fast-reroute per-prefix

fast-reroute per-prefix remote-lfa tunnel mpls-ldp

metric 20 level 1

mpls ldp sync

!

address-family ipv6 unicast

metric 3000 level

As per document , below is recommended from ASR903 RSP3C BFD over Port-Channel

BFD over port-channel (PoCH) is supported on the RSP3 module in software offload mode only. The minimum timer value supported is 200 milliseconds.

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_bfd/configuration/xe-3s/asr903/16-12-1/b-i...

AG1-2-903#sh run | in platform bfd-offload

platform bfd-offload-timer 200000 >> minimum 200ms is supported on Portchannel

AG1-2-903#sh run | b bfd-template

bfd-template single-hop 200ms

interval min-tx 200 min-rx 200 multiplier 3 >>>> 200ms * 3 timer

AG1-2-903#conf t

Enter configuration commands, one per line. End with CNTL/Z.

AG1-2-903(config)#int po10

AG1-2-903(config-if)#no bfd template AG1-ASR9K

AG1-2-903(config-if)#bfd template 200ms

AG1-2-903(config-if)#

RP/0/RP0/CPU0:ASR9K_1#sh bfd session interface be1601 detail

Mon Oct 25 03:01:29.377 EDT

I/f: Bundle-Ether1601, Location: 0/7/CPU0

Dest: 172.27.98.220

Src: 172.27.98.221

State: UP for 0d:0h:0m:13s, number of times UP: 1

Session type: SW/V4/SH/BL

Received parameters:

Version: 1, desired tx interval: 200 ms, required rx interval: 200 ms >>>

Required echo rx interval: 0 ms, multiplier: 3, diag: None

My discr: 1026, your discr: 131077, state UP, D/F/P/C/A: 0/0/0/0/0

Transmitted parameters:

Version: 1, desired tx interval: 50 ms, required rx interval: 50 ms

Required echo rx interval: 0 ms, multiplier: 3, diag: None

My discr: 131077, your discr: 1026, state UP, D/F/P/C/A: 0/0/0/1/0

Timer Values:

Local negotiated async tx interval: 200 ms

Remote negotiated async tx interval: 200 ms

Desired echo tx interval: 0 s, local negotiated echo tx interval: 0 ms

Echo detection time: 0 ms(0 ms*3), async detection time: 600 ms(200 ms*3)

Label:

Internal label: 506618/0x7bafa

Local Stats:

Intervals between async packets:

Tx: Number of intervals=100, min=1 ms, max=1994 ms, avg=632 ms >>> TX working

Last packet transmitted 85 ms ago

Rx: Number of intervals=78, min=1 ms, max=201 ms, avg=167 ms >>> RX working

Last packet received 106 ms ago

Intervals between echo packets:

Tx: Number of intervals=0, min=0 s, max=0 s, avg=0 s

Last packet transmitted 0 s ago

Rx: Number of intervals=0, min=0 s, max=0 s, avg=0 s

Last packet received 0 s ago

Latency of echo packets (time between tx and rx):

Number of packets: 0, min=0 ms, max=0 ms, avg=0 ms

MP download state: BFD_MP_DOWNLOAD_ACK

State change time: Oct 25 02:50:53.628

Session owner information:

Desired Adjusted

Client Interval Multiplier Interval Multiplier

-------------------- --------------------- ---------------------

isis-CORE 50 ms 3 50 ms 3

ISIS & RIB check

Below status with 200ms BFD on ASR903

AG1-2-903#sh isis neighbors 

Tag CORE:

System Id       Type Interface     IP Address      State Holdtime Circuit Id

EAG5            L1   Te0/3/7       172.29.4.0      UP    27       00

EAG5            L1   Te0/4/5       172.29.4.2      UP    25       00

ASR9K_1           L1   Po10          172.27.98.221   UP    26       00

AG2-2           L1   Te0/3/2       172.29.5.1      UP    26       00

AG1-2-903#sh ip route 10.12.0.3    

Routing entry for 10.12.0.3/32

  Known via "isis", distance 115, metric 10

  Tag 5000, type level-1

  Redistributing via isis CORE

  Last update from 172.27.98.221 on Port-channel10, 00:00:34 ago

  Routing Descriptor Blocks:

  * 172.27.98.221, from 10.12.0.3, 00:00:34 ago, via Port-channel10  >>> So now PO10 is UP 

      Route metric is 10, traffic share count is 1

      Route tag 5000

      Repair Path: 172.29.5.1, via TenGigabitEthernet0/3/2