Monday, January 22, 2018

BFD task #2. BFD for BGP.

Topology:



Use configuration from BFD task #1 as initial configuration for this task.
Router R6 is added to the topology. 

Requirements: 

1. Configure link between routers R6 and R4. 
2. Configure eBGP session between routers R4 and R6. 
3. Configure full-mesh of iBGP sessions between routers in AS24. Use loopback0 addresses for             iBGP peerings. 
4. Configure all BGP sessions for sub-second convergence. Don't change BGP session timers. 
5. When possible, reduce the load on routers CPU introduced by BFD, by only processing BFD               packets every 20 seconds. 

Solution:

Highlight the text below to reveal the solution.

This task requires understanding of BFD configuration for BGP, multihop BFD configuration, and BFD slow-timers.

Requirement #4 - use multihop-BFD to activate BFD for iBGP peerings. You will need to configure bfd-multihop template and bfd map, then configure the BGP peers for BFD.

Requiremetn #5 - configure BFD slow-timers with value of 20000 msec. This will reduce the rate of BFD control packets to every 20 seconds, instead of every 1 second, but only for BFD sessions in echo mode.

R1, R2, R3, & R5: 


!
bfd slow-timers 20000
bfd map ipv4  24.0.0.0/16  24.0.0.0/16 MH
bfd-template multi-hop MH
 interval min-tx 250 min-rx 250 multiplier 3
!
!
router bgp 24
 bgp log-neighbor-changes
 neighbor IBGP peer-group
 neighbor IBGP remote-as 24
 neighbor IBGP update-source Loopback0
 neighbor IBGP fall-over bfd
 ..
 ..
!

R4:


bfd slow-timers 20000
bfd map ipv4  24.0.0.0/16  24.0.0.0/16 MH
bfd-template multi-hop MH
 interval min-tx 250 min-rx 250 multiplier 3
!
!
interface Ethernet1/0
 ip address 24.0.46.4 255.255.255.0
 bfd interval 250 min_rx 250 multiplier 3
!
!
router bgp 24
 bgp log-neighbor-changes
 neighbor IBGP peer-group
 neighbor IBGP remote-as 24
 neighbor IBGP update-source Loopback0
 neighbor IBGP fall-over bfd
 neighbor 24.0.1.1 peer-group IBGP
 neighbor 24.0.2.2 peer-group IBGP
 neighbor 24.0.3.3 peer-group IBGP
 neighbor 24.0.5.5 peer-group IBGP
 neighbor 24.0.46.6 remote-as 6
 neighbor 24.0.46.6 fall-over bfd
!



R6:


!
interface Ethernet0/0
 ip address 24.0.46.6 255.255.255.0
 bfd interval 250 min_rx 250 multiplier 3
!
!
router bgp 6
 bgp log-neighbor-changes
 neighbor 24.0.46.4 remote-as 24
 neighbor 24.0.46.4 fall-over bfd
!

Verification:


R1#               show bfd neighbors

IPv4 Sessions
NeighAddr                              LD/RD         RH/RS     State     Int
24.0.10.2                               3/3          Up        Up        Et0/0
24.0.10.3                               2/2          Up        Up        Et0/0
24.0.40.5                               1/2          Up        Up        Et0/1

IPv4 Multihop Sessions
NeighAddr[vrf]                                LD/RD         RH/RS     State
24.0.2.2                                       4/5          Up        Up
24.0.3.3                                       5/6          Up        Up
24.0.4.4                                       9/5          Up        Up
24.0.5.5                                       8/9          Up        Up


R1#               show bfd neighbors  details

IPv4 Sessions
NeighAddr                              LD/RD         RH/RS     State     Int
24.0.10.2                               3/3          Up        Up        Et0/0
Session state is UP and using echo function with 250 ms interval.
Session Host: Software
OurAddr: 24.0.10.1
Handle: 3
Local Diag: 0, Demand mode: 0, Poll bit: 0
MinTxInt: 20000000, MinRxInt: 20000000, Multiplier: 3
Received MinRxInt: 20000000, Received Multiplier: 3
Holddown (hits): 0(0), Hello (hits): 20000(8609)
Rx Count: 8613, Rx Interval (ms) min/max/avg: 1/19954/1677 last: 3448 ms ago
Tx Count: 8614, Tx Interval (ms) min/max/avg: 1/19983/1661 last: 17741 ms ago
Elapsed time watermarks: 0 0 (last: 0)
Registered protocols: OSPF
Uptime: 02:20:18
Last packet: Version: 1                  - Diagnostic: 0
             State bit: Up               - Demand bit: 0
             Poll bit: 0                 - Final bit: 0
             C bit: 0
             Multiplier: 3               - Length: 24
             My Discr.: 3                - Your Discr.: 3
             Min tx interval: 20000000   - Min rx interval: 20000000
             Min Echo interval: 250000

IPv4 Sessions
NeighAddr                              LD/RD         RH/RS     State     Int
24.0.10.3                               2/2          Up        Up        Et0/0
Session state is UP and using echo function with 250 ms interval.
Session Host: Software
OurAddr: 24.0.10.1
Handle: 2
Local Diag: 0, Demand mode: 0, Poll bit: 0
MinTxInt: 20000000, MinRxInt: 20000000, Multiplier: 3
Received MinRxInt: 20000000, Received Multiplier: 3
Holddown (hits): 0(0), Hello (hits): 20000(8611)
Rx Count: 8629, Rx Interval (ms) min/max/avg: 1/20002/1676 last: 321 ms ago
Tx Count: 8616, Tx Interval (ms) min/max/avg: 1/19924/1665 last: 13155 ms ago
Elapsed time watermarks: 0 0 (last: 0)
Registered protocols: OSPF
Uptime: 02:20:21
Last packet: Version: 1                  - Diagnostic: 0
             State bit: Up               - Demand bit: 0
             Poll bit: 0                 - Final bit: 0
             C bit: 0
             Multiplier: 3               - Length: 24
             My Discr.: 2                - Your Discr.: 2
             Min tx interval: 20000000   - Min rx interval: 20000000
             Min Echo interval: 250000

IPv4 Sessions
NeighAddr                              LD/RD         RH/RS     State     Int
24.0.40.5                               1/2          Up        Up        Et0/1
Session state is UP and not using echo function.
Session Host: Software
OurAddr: 24.0.40.1
Handle: 1
Local Diag: 0, Demand mode: 0, Poll bit: 0
MinTxInt: 250000, MinRxInt: 250000, Multiplier: 3
Received MinRxInt: 250000, Received Multiplier: 3
Holddown (hits): 718(0), Hello (hits): 250(37946)
Rx Count: 37960, Rx Interval (ms) min/max/avg: 24/281/221 last: 33 ms ago
Tx Count: 37948, Tx Interval (ms) min/max/avg: 1/294/221 last: 15 ms ago
Elapsed time watermarks: 0 0 (last: 0)
Registered protocols: OSPF
Uptime: 02:20:21
Last packet: Version: 1                  - Diagnostic: 0
             State bit: Up               - Demand bit: 0
             Poll bit: 0                 - Final bit: 0
             C bit: 0
             Multiplier: 3               - Length: 24
             My Discr.: 2                - Your Discr.: 1
             Min tx interval: 250000     - Min rx interval: 250000
             Min Echo interval: 0

IPv4 Multihop Sessions
NeighAddr[vrf]                                LD/RD         RH/RS     State
24.0.2.2                                       4/5          Up        Up
Session state is UP and not using echo function.
Session Host: Software
OurAddr: 24.0.1.1
Handle: 5
Local Diag: 0, Demand mode: 0, Poll bit: 0
MinTxInt: 250000, MinRxInt: 250000, Multiplier: 3
Received MinRxInt: 250000, Received Multiplier: 3
Holddown (hits): 548(0), Hello (hits): 250(11709)
Rx Count: 4233, Rx Interval (ms) min/max/avg: 1/271/222 last: 202 ms ago
Tx Count: 4227, Tx Interval (ms) min/max/avg: 1/258/221 last: 105 ms ago
Elapsed time watermarks: 0 0 (last: 0)
Registered protocols: BGP
Map information:
 Destination[vrf]: 24.0.0.0/16
 Source[vrf]: 24.0.0.0/16
 Template: MH
 Authentication(Type/Keychain): invalid_type/
Uptime: 00:15:37
Last packet: Version: 1                  - Diagnostic: 0
             State bit: Up               - Demand bit: 0
             Poll bit: 0                 - Final bit: 0
             C bit: 0
             Multiplier: 3               - Length: 24
             My Discr.: 5                - Your Discr.: 4
             Min tx interval: 250000     - Min rx interval: 250000
             Min Echo interval: 0

IPv4 Multihop Sessions
NeighAddr[vrf]                                LD/RD         RH/RS     State
24.0.3.3                                       5/6          Up        Up
Session state is UP and not using echo function.
Session Host: Software
OurAddr: 24.0.1.1
Handle: 4
Local Diag: 0, Demand mode: 0, Poll bit: 0
MinTxInt: 250000, MinRxInt: 250000, Multiplier: 3
Received MinRxInt: 250000, Received Multiplier: 3
Holddown (hits): 680(0), Hello (hits): 250(11679)
Rx Count: 4179, Rx Interval (ms) min/max/avg: 1/258/222 last: 70 ms ago
Tx Count: 4180, Tx Interval (ms) min/max/avg: 1/267/222 last: 220 ms ago
Elapsed time watermarks: 0 0 (last: 0)
Registered protocols: BGP
Map information:
 Destination[vrf]: 24.0.0.0/16
 Source[vrf]: 24.0.0.0/16
 Template: MH
 Authentication(Type/Keychain): invalid_type/
Uptime: 00:15:27
Last packet: Version: 1                  - Diagnostic: 0
             State bit: Up               - Demand bit: 0
             Poll bit: 0                 - Final bit: 0
             C bit: 0
             Multiplier: 3               - Length: 24
             My Discr.: 6                - Your Discr.: 5
             Min tx interval: 250000     - Min rx interval: 250000
             Min Echo interval: 0

IPv4 Multihop Sessions
NeighAddr[vrf]                                LD/RD         RH/RS     State
24.0.4.4                                       9/5          Up        Up
Session state is UP and not using echo function.
Session Host: Software
OurAddr: 24.0.1.1
Handle: 6
Local Diag: 0, Demand mode: 0, Poll bit: 0
MinTxInt: 250000, MinRxInt: 250000, Multiplier: 3
Received MinRxInt: 250000, Received Multiplier: 3
Holddown (hits): 681(0), Hello (hits): 250(4444)
Rx Count: 4154, Rx Interval (ms) min/max/avg: 16/260/222 last: 69 ms ago
Tx Count: 4149, Tx Interval (ms) min/max/avg: 2/258/222 last: 100 ms ago
Elapsed time watermarks: 0 0 (last: 0)
Registered protocols: BGP
Map information:
 Destination[vrf]: 24.0.0.0/16
 Source[vrf]: 24.0.0.0/16
 Template: MH
 Authentication(Type/Keychain): invalid_type/
Uptime: 00:15:20
Last packet: Version: 1                  - Diagnostic: 0
             State bit: Up               - Demand bit: 0
             Poll bit: 0                 - Final bit: 0
             C bit: 0
             Multiplier: 3               - Length: 24
             My Discr.: 5                - Your Discr.: 9
             Min tx interval: 250000     - Min rx interval: 250000
             Min Echo interval: 0

IPv4 Multihop Sessions
NeighAddr[vrf]                                LD/RD         RH/RS     State
24.0.5.5                                       8/9          Up        Up
Session state is UP and not using echo function.
Session Host: Software
OurAddr: 24.0.1.1
Handle: 7
Local Diag: 0, Demand mode: 0, Poll bit: 0
MinTxInt: 250000, MinRxInt: 250000, Multiplier: 3
Received MinRxInt: 250000, Received Multiplier: 3
Holddown (hits): 693(0), Hello (hits): 250(5825)
Rx Count: 5821, Rx Interval (ms) min/max/avg: 1/267/222 last: 57 ms ago
Tx Count: 5828, Tx Interval (ms) min/max/avg: 1/257/221 last: 192 ms ago
Elapsed time watermarks: 0 0 (last: 0)
Registered protocols: BGP
Map information:
 Destination[vrf]: 24.0.0.0/16
 Source[vrf]: 24.0.0.0/16
 Template: MH
 Authentication(Type/Keychain): invalid_type/
Uptime: 00:21:31
Last packet: Version: 1                  - Diagnostic: 0
             State bit: Up               - Demand bit: 0
             Poll bit: 0                 - Final bit: 0
             C bit: 0
             Multiplier: 3               - Length: 24
             My Discr.: 9                - Your Discr.: 8
             Min tx interval: 250000     - Min rx interval: 250000
             Min Echo interval: 0


R4#                     show bfd neighbors

IPv4 Sessions
NeighAddr                              LD/RD         RH/RS     State     Int
24.0.20.3                               2/5          Up        Up        Et0/0
24.0.20.5                               1/12         Up        Up        Et0/0
24.0.30.2                               3/4          Up        Up        Et0/1
24.0.46.6                               4/1          Up        Up        Et1/0

IPv4 Multihop Sessions
NeighAddr[vrf]                                LD/RD         RH/RS     State
24.0.1.1                                       5/9          Up        Up
24.0.2.2                                       6/7          Up        Up
24.0.3.3                                       7/8          Up        Up
24.0.5.5                                       8/13         Up        Up
R4#sho
R4#show bf
R4#show bfd nei
R4#show bfd neighbors deta
R4#show bfd neighbors details

IPv4 Sessions
NeighAddr                              LD/RD         RH/RS     State     Int
24.0.20.3                               2/5          Up        Up        Et0/0
Session state is UP and using echo function with 250 ms interval.
Session Host: Software
OurAddr: 24.0.20.4
Handle: 2
Local Diag: 0, Demand mode: 0, Poll bit: 0
MinTxInt: 20000000, MinRxInt: 20000000, Multiplier: 3
Received MinRxInt: 20000000, Received Multiplier: 3
Holddown (hits): 0(0), Hello (hits): 20000(214)
Rx Count: 221, Rx Interval (ms) min/max/avg: 1/19993/5860 last: 9513 ms ago
Tx Count: 218, Tx Interval (ms) min/max/avg: 1/19861/5915 last: 15078 ms ago
Elapsed time watermarks: 0 0 (last: 0)
Registered protocols: OSPF
Uptime: 00:21:38
Last packet: Version: 1                  - Diagnostic: 0
             State bit: Up               - Demand bit: 0
             Poll bit: 0                 - Final bit: 0
             C bit: 0
             Multiplier: 3               - Length: 24
             My Discr.: 5                - Your Discr.: 2
             Min tx interval: 20000000   - Min rx interval: 20000000
             Min Echo interval: 250000

IPv4 Sessions
NeighAddr                              LD/RD         RH/RS     State     Int
24.0.20.5                               1/12         Up        Up        Et0/0
Session state is UP and using echo function with 250 ms interval.
Session Host: Software
OurAddr: 24.0.20.4
Handle: 1
Local Diag: 0, Demand mode: 0, Poll bit: 0
MinTxInt: 20000000, MinRxInt: 20000000, Multiplier: 3
Received MinRxInt: 20000000, Received Multiplier: 3
Holddown (hits): 0(0), Hello (hits): 20000(217)
Rx Count: 223, Rx Interval (ms) min/max/avg: 1/20007/5797 last: 15649 ms ago
Tx Count: 222, Tx Interval (ms) min/max/avg: 1/19984/5883 last: 2565 ms ago
Elapsed time watermarks: 0 0 (last: 0)
Registered protocols: OSPF
Uptime: 00:21:42
Last packet: Version: 1                  - Diagnostic: 0
             State bit: Up               - Demand bit: 0
             Poll bit: 0                 - Final bit: 0
             C bit: 0
             Multiplier: 3               - Length: 24
             My Discr.: 12               - Your Discr.: 1
             Min tx interval: 20000000   - Min rx interval: 20000000
             Min Echo interval: 250000

IPv4 Sessions
NeighAddr                              LD/RD         RH/RS     State     Int
24.0.30.2                               3/4          Up        Up        Et0/1
Session state is UP and not using echo function.
Session Host: Software
OurAddr: 24.0.30.4
Handle: 7
Local Diag: 0, Demand mode: 0, Poll bit: 0
MinTxInt: 250000, MinRxInt: 250000, Multiplier: 3
Received MinRxInt: 250000, Received Multiplier: 3
Holddown (hits): 577(0), Hello (hits): 250(5844)
Rx Count: 5839, Rx Interval (ms) min/max/avg: 2/258/222 last: 173 ms ago
Tx Count: 5847, Tx Interval (ms) min/max/avg: 1/261/221 last: 65 ms ago
Elapsed time watermarks: 0 0 (last: 0)
Registered protocols: OSPF
Uptime: 00:21:33
Last packet: Version: 1                  - Diagnostic: 0
             State bit: Up               - Demand bit: 0
             Poll bit: 0                 - Final bit: 0
             C bit: 0
             Multiplier: 3               - Length: 24
             My Discr.: 4                - Your Discr.: 3
             Min tx interval: 250000     - Min rx interval: 250000
             Min Echo interval: 0

IPv4 Sessions
NeighAddr                              LD/RD         RH/RS     State     Int
24.0.46.6                               4/1          Up        Up        Et1/0
Session state is UP and using echo function with 250 ms interval.
Session Host: Software
OurAddr: 24.0.46.4
Handle: 8
Local Diag: 0, Demand mode: 0, Poll bit: 0
MinTxInt: 20000000, MinRxInt: 20000000, Multiplier: 3
Received MinRxInt: 20000000, Received Multiplier: 3
Holddown (hits): 0(0), Hello (hits): 20000(64)
Rx Count: 66, Rx Interval (ms) min/max/avg: 1/19989/17146 last: 15620 ms ago
Tx Count: 65, Tx Interval (ms) min/max/avg: 15130/19968/17532 last: 8095 ms ago
Elapsed time watermarks: 0 0 (last: 0)
Registered protocols: BGP
Uptime: 00:18:50
Last packet: Version: 1                  - Diagnostic: 0
             State bit: Up               - Demand bit: 0
             Poll bit: 0                 - Final bit: 0
             C bit: 0
             Multiplier: 3               - Length: 24
             My Discr.: 1                - Your Discr.: 4
             Min tx interval: 20000000   - Min rx interval: 20000000
             Min Echo interval: 250000

IPv4 Multihop Sessions
NeighAddr[vrf]                                LD/RD         RH/RS     State
24.0.1.1                                       5/9          Up        Up
Session state is UP and not using echo function.
Session Host: Software
OurAddr: 24.0.4.4
Handle: 6
Local Diag: 0, Demand mode: 0, Poll bit: 0
MinTxInt: 250000, MinRxInt: 250000, Multiplier: 3
Received MinRxInt: 250000, Received Multiplier: 3
Holddown (hits): 671(0), Hello (hits): 250(4683)
Rx Count: 4679, Rx Interval (ms) min/max/avg: 1/259/222 last: 79 ms ago
Tx Count: 4686, Tx Interval (ms) min/max/avg: 11/260/221 last: 95 ms ago
Elapsed time watermarks: 0 0 (last: 0)
Registered protocols: BGP
Map information:
 Destination[vrf]: 24.0.0.0/16
 Source[vrf]: 24.0.0.0/16
 Template: MH
 Authentication(Type/Keychain): invalid_type/
Uptime: 00:17:18
Last packet: Version: 1                  - Diagnostic: 0
             State bit: Up               - Demand bit: 0
             Poll bit: 0                 - Final bit: 0
             C bit: 0
             Multiplier: 3               - Length: 24
             My Discr.: 9                - Your Discr.: 5
             Min tx interval: 250000     - Min rx interval: 250000
             Min Echo interval: 0

IPv4 Multihop Sessions
NeighAddr[vrf]                                LD/RD         RH/RS     State
24.0.2.2                                       6/7          Up        Up
Session state is UP and not using echo function.
Session Host: Software
OurAddr: 24.0.4.4
Handle: 4
Local Diag: 0, Demand mode: 0, Poll bit: 0
MinTxInt: 250000, MinRxInt: 250000, Multiplier: 3
Received MinRxInt: 250000, Received Multiplier: 3
Holddown (hits): 572(0), Hello (hits): 250(4682)
Rx Count: 4676, Rx Interval (ms) min/max/avg: 1/262/222 last: 178 ms ago
Tx Count: 4685, Tx Interval (ms) min/max/avg: 5/258/222 last: 34 ms ago
Elapsed time watermarks: 0 0 (last: 0)
Registered protocols: BGP
Map information:
 Destination[vrf]: 24.0.0.0/16
 Source[vrf]: 24.0.0.0/16
 Template: MH
 Authentication(Type/Keychain): invalid_type/
Uptime: 00:17:18
Last packet: Version: 1                  - Diagnostic: 0
             State bit: Up               - Demand bit: 0
             Poll bit: 0                 - Final bit: 0
             C bit: 0
             Multiplier: 3               - Length: 24
             My Discr.: 7                - Your Discr.: 6
             Min tx interval: 250000     - Min rx interval: 250000
             Min Echo interval: 0

IPv4 Multihop Sessions
NeighAddr[vrf]                                LD/RD         RH/RS     State
24.0.3.3                                       7/8          Up        Up
Session state is UP and not using echo function.
Session Host: Software
OurAddr: 24.0.4.4
Handle: 5
Local Diag: 0, Demand mode: 0, Poll bit: 0
MinTxInt: 250000, MinRxInt: 250000, Multiplier: 3
Received MinRxInt: 250000, Received Multiplier: 3
Holddown (hits): 696(0), Hello (hits): 250(4676)
Rx Count: 4681, Rx Interval (ms) min/max/avg: 1/259/221 last: 54 ms ago
Tx Count: 4679, Tx Interval (ms) min/max/avg: 3/258/222 last: 53 ms ago
Elapsed time watermarks: 0 0 (last: 0)
Registered protocols: BGP
Map information:
 Destination[vrf]: 24.0.0.0/16
 Source[vrf]: 24.0.0.0/16
 Template: MH
 Authentication(Type/Keychain): invalid_type/
Uptime: 00:17:18
Last packet: Version: 1                  - Diagnostic: 0
             State bit: Up               - Demand bit: 0
             Poll bit: 0                 - Final bit: 0
             C bit: 0
             Multiplier: 3               - Length: 24
             My Discr.: 8                - Your Discr.: 7
             Min tx interval: 250000     - Min rx interval: 250000
             Min Echo interval: 0

IPv4 Multihop Sessions
NeighAddr[vrf]                                LD/RD         RH/RS     State
24.0.5.5                                       8/13         Up        Up
Session state is UP and not using echo function.
Session Host: Software
OurAddr: 24.0.4.4
Handle: 3
Local Diag: 0, Demand mode: 0, Poll bit: 0
MinTxInt: 250000, MinRxInt: 250000, Multiplier: 3
Received MinRxInt: 250000, Received Multiplier: 3
Holddown (hits): 601(0), Hello (hits): 250(4682)
Rx Count: 4678, Rx Interval (ms) min/max/avg: 1/283/222 last: 149 ms ago
Tx Count: 4685, Tx Interval (ms) min/max/avg: 7/257/222 last: 104 ms ago
Elapsed time watermarks: 0 0 (last: 0)
Registered protocols: BGP
Map information:
 Destination[vrf]: 24.0.0.0/16
 Source[vrf]: 24.0.0.0/16
 Template: MH
 Authentication(Type/Keychain): invalid_type/
Uptime: 00:17:18
Last packet: Version: 1                  - Diagnostic: 0
             State bit: Up               - Demand bit: 0
             Poll bit: 0                 - Final bit: 0
             C bit: 0
             Multiplier: 3               - Length: 24
             My Discr.: 13               - Your Discr.: 8
             Min tx interval: 250000     - Min rx interval: 250000
             Min Echo interval: 0


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