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IP SLA

Cisco IP Service Level Agreement (SLA) feature -

Cisco IOS IP SLAs allow paths to be changed based on network conditions such as jitter,latency, load and other factors.

Over here used icmp parameter to check router reachability and also tracking router reachability.Configured static route.

Traffic to moved from one ISP to another ISP incase of link failure and back to again primary after restoration of link.

 

With Cisco IOS Release 12.4(4)T, 12.2(33)SB, and 12.2(33)SXI, the ip sla command has replaced the previous ip sla monitor command. In addition, the icmp-echo command has replaced the type echo protocol ipIcmpEcho command.

ip sla 1

icmp-echo x.x.x.x (destination address)

 

For detailed information refer:

Link: http://www.cisco.com/en/US/docs/switches/lan/catalyst4500/12.2/44sg/configuration/guide/swipsla.html

 

IP SLA Configuration:

 

Topology:

Configuration:

 

Branch Config:

R1#sh running-config

Building configuration...

Current configuration : 1683 bytes

version 12.4

service timestamps debug datetime msec

service timestamps log datetime msec

no service password-encryptio

 

hostname R1

boot-start-marker

boot-end-marker

no aaa new-model

memory-size iomem 5

ip cef

no ip domain lookup

 

ip domain name lab.local

 

ip auth-proxy max-nodata-conns 3

 

ip admission max-nodata-conns 3

 

ip sla monitor 11

 

type echo protocol ipIcmpEcho 209.165.203.1

 

frequency 10

 

ip sla monitor schedule 11 life forever start-time now

 

ip sla monitor 22

 

type echo protocol ipIcmpEcho 209.165.204.1

 

frequency 10

 

ip sla monitor schedule 22 life forever start-time now

 

!

 

track 1 rtr 11 reachability

 

delay down 10 up 1

 

!

 

track 2 rtr 22 reachability

 

delay down 10 up 1

 

!

 

interface Loopback0

 

description R1 lan

 

ip address 192.168.1.1 255.255.255.0

 

!

 

interface Serial0/0

 

description R1-->ISP1

 

bandwidth 128

 

ip address 209.165.201.2 255.255.255.252

 

serial restart-delay 0

 

clock rate 128000

 

!

 

interface Serial0/1

 

description R1-->ISP2

 

bandwidth 128

 

ip address 209.165.202.130 255.255.255.252

 

serial restart-delay 0

 

clock rate 128000

 

!

 

interface Serial0/2

 

no ip address

 

shutdown

 

serial restart-delay 0

 

!

 

interface Serial0/3

 

no ip address

 

shutdown

 

serial restart-delay 0

 

!

 

no ip http server

 

no ip http secure-server

 

!

 

ip forward-protocol nd

 

ip route 0.0.0.0 0.0.0.0 209.165.201.1 2 track 1

 

ip route 0.0.0.0 0.0.0.0 209.165.202.129 3 track 2

 

ip route 0.0.0.0 0.0.0.0 209.165.201.1 5

 

!

 

control-plane

 

!

 

line con 0

 

exec-timeout 0 0

 

privilege level 15

 

logging synchronous

 

line aux 0

 

exec-timeout 0 0

 

privilege level 15

 

logging synchronous

 

line vty 0 4

 

login

 

!

 

end

 

R1#

 

ISP1 Config:

 

 

 

R2#sh running-config

 

Building configuration...

 

 

 

Current configuration : 1428 bytes

 

!

 

version 12.4

 

service timestamps debug datetime msec

 

service timestamps log datetime msec

 

no service password-encryption

 

!

 

hostname R2

 

!

 

boot-start-marker

 

boot-end-marker

 

!

 

!

 

no aaa new-model

 

memory-size iomem 5

 

!

 

!

 

ip cef

 

no ip domain lookup

 

ip domain name lab.local

 

!

 

!

 

ip auth-proxy max-nodata-conns 3

 

ip admission max-nodata-conns 3

 

!

 

Loopback0

 

description web server

 

ip address 209.165.200.254 255.255.255.255

 

!

 

interface Loopback1

 

description IPS1 DNS Server

 

ip address 209.165.203.1 255.255.255.255

 

!

 

interface Serial0/0

 

description ISP1-->R1

 

bandwidth 128

 

ip address 209.165.201.1 255.255.255.252

 

serial restart-delay 0

 

clock rate 128000

 

!

 

interface Serial0/1

 

bandwidth 128

 

ip address 209.165.200.225 255.255.255.252

 

serial restart-delay 0

 

clock rate 128000

 

!

 

interface Serial0/2

 

no ip address

 

shutdown

 

serial restart-delay 0

 

!

 

interface Serial0/3

 

no ip address

 

shutdown

 

serial restart-delay 0

 

!

 

router eigrp 1

 

network 209.165.200.224 0.0.0.3

 

network 209.165.201.0 0.0.0.3

 

network 209.165.203.0

 

no auto-summary

 

!

 

no ip http server

 

no ip http secure-server

 

!

 

ip forward-protocol nd

 

ip route 192.168.1.0 255.255.255.0 209.165.201.2

 

!

 

control-plane

 

!

 

line con 0

 

exec-timeout 0 0

 

privilege level 15

 

logging synchronous

 

line aux 0

 

exec-timeout 0 0

 

privilege level 15

 

logging synchronous

 

line vty 0 4

 

login

 

!

 

!

 

end

 

R2#

 

 

 

ISP2 Config:

 

 

 

R3#sh running-config

 

Building configuration...

 

 

 

Current configuration : 1459 bytes

 

!

 

version 12.4

 

service timestamps debug datetime msec

 

service timestamps log datetime msec

 

no service password-encryption

 

!

 

hostname R3

 

!

 

boot-start-marker

 

boot-end-marker

 

!

 

!

 

no aaa new-model

 

memory-size iomem 5

 

!

 

!

 

ip cef

 

no ip domain lookup

 

ip domain name lab.local

 

!

 

!

 

ip auth-proxy max-nodata-conns 3

 

ip admission max-nodata-conns 3

 

!

 

interface Loopback0

 

description Web Server

 

ip address 209.165.200.254 255.255.255.255

 

!

 

interface Loopback1

 

description ISP2 DNS Server

 

ip address 209.165.204.1 255.255.255.255

 

!

 

interface Serial0/0

 

description ISP2-->R1

 

bandwidth 128

 

ip address 209.165.202.129 255.255.255.252

 

serial restart-delay 0

 

clock rate 128000

 

!

 

interface Serial0/1

 

description ISP2-->ISP1

 

bandwidth 128

 

ip address 209.165.200.226 255.255.255.252

 

serial restart-delay 0

 

clock rate 128000

 

!

 

interface Serial0/2

 

no ip address

 

shutdown

 

serial restart-delay 0

 

!

 

interface Serial0/3

 

no ip address

 

shutdown

 

serial restart-delay 0

 

!

 

router eigrp 1

 

network 209.165.200.224 0.0.0.3

 

network 209.165.202.128 0.0.0.3

 

network 209.165.204.0

 

no auto-summary

 

!

 

no ip http server

 

no ip http secure-server

 

!

 

ip forward-protocol nd

 

ip route 192.168.1.0 255.255.255.0 209.165.202.130

 

!

 

control-plane

 

!

 

line con 0

 

exec-timeout 0 0

 

privilege level 15

 

logging synchronous

 

line aux 0

 

exec-timeout 0 0

 

privilege level 15

 

logging synchronous

 

line vty 0 4

 

login

 

!

 

!

 

end

 

 

 

R3#

 

 

 

Troubleshooting:

 

R1#sh interface description

 

Interface                     Status                 Protocol Description

 

Se0/0                          up             up       R1-->ISP1

 

Se0/1                          up             up       R1-->ISP2

 

Se0/2                          admin down      down

 

Se0/3                          admin down      down

 

Lo0                              up             up        R1 lan

 

 

 

 

 

R1#sh ip sla monitor configuration 11

 

IP SLA Monitor, Infrastructure Engine-II.

 

Entry number: 11

 

Owner:

 

Tag:

 

Type of operation to perform: echo

 

Target address: 209.165.203.1

 

Request size (ARR data portion): 28

 

Operation timeout (milliseconds): 5000

 

Type Of Service parameters: 0x0

 

Verify data: No

 

Operation frequency (seconds): 10

 

Next Scheduled Start Time: Start Time already passed

 

Group Scheduled : FALSE

 

Life (seconds): Forever

 

Entry Ageout (seconds): never

 

Recurring (Starting Everyday): FALSE

 

Status of entry (SNMP RowStatus): Active

 

Threshold (milliseconds): 5000

 

Number of statistic hours kept: 2

 

Number of statistic distribution buckets kept: 1

 

Statistic distribution interval (milliseconds): 20

 

Number of history Lives kept: 0

 

Number of history Buckets kept: 15

 

History Filter Type: None

 

Enhanced History:

 

 

 

R1#sh ip sla monitor configuration 22

 

IP SLA Monitor, Infrastructure Engine-II.

 

Entry number: 22

 

Owner:

 

Tag:

 

Type of operation to perform: echo

 

Target address: 209.165.204.1

 

Request size (ARR data portion): 28

 

Operation timeout (milliseconds): 5000

 

Type Of Service parameters: 0x0

 

Verify data: No

 

Operation frequency (seconds): 10

 

Next Scheduled Start Time: Start Time already passed

 

Group Scheduled : FALSE

 

Life (seconds): Forever

 

Entry Ageout (seconds): never

 

Recurring (Starting Everyday): FALSE

 

Status of entry (SNMP RowStatus): Active

 

Threshold (milliseconds): 5000

 

Number of statistic hours kept: 2

 

Number of statistic distribution buckets kept: 1

 

Statistic distribution interval (milliseconds): 20

 

Number of history Lives kept: 0

 

Number of history Buckets kept: 15

 

History Filter Type: None

 

Enhanced History:

 

 

 

R1#sh ip sla monitor statistics

 

Round trip time (RTT)   Index 11

 

        Latest RTT: 95 ms

 

Latest operation start time: *00:26:53.151 UTC Fri Mar 1 2002

 

Latest operation return code: OK

 

Number of successes: 148

 

Number of failures: 13

 

Operation time to live: Forever

 

 

 

Round trip time (RTT)   Index 22

 

        Latest RTT: 121 ms

 

Latest operation start time: *00:26:53.159 UTC Fri Mar 1 2002

 

Latest operation return code: OK

 

Number of successes: 147

 

Number of failures: 14

 

Operation time to live: Forever

 

 

 

R1#sh ip route

 

Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP

 

       D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

 

       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

 

       E1 - OSPF external type 1, E2 - OSPF external type 2

 

       i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2

 

       ia - IS-IS inter area, * - candidate default, U - per-user static route

 

       o - ODR, P - periodic downloaded static route

 

 

 

Gateway of last resort is 209.165.201.1 to network 0.0.0.0

 

 

 

     209.165.201.0/30 is subnetted, 1 subnets

 

C       209.165.201.0 is directly connected, Serial0/0

 

     209.165.202.0/30 is subnetted, 1 subnets

 

C       209.165.202.128 is directly connected, Serial0/1

 

C    192.168.1.0/24 is directly connected, Loopback0

 

S*   0.0.0.0/0 [2/0] via 209.165.201.1

 

 

 

Testing SLA working:

 

Reachablity to ISP1 goes down

 

ISP1(config)#interface loopback 1

 

ISP1(config-if)#shutdown

 

ISP1(config-if)#

 

*Mar  1 00:49:32.983: %LINK-5-CHANGED: Interface Loopback1, changed state to administratively down

 

*Mar  1 00:49:33.983: %LINEPROTO-5-UPDOWN: Line protocol on Interface Loopback1, changed state to down

 

ISP1(config-if)#^Z

 

ISP1#

 

*Mar  1 00:49:37.083: %SYS-5-CONFIG_I: Configured from console by console

 

 

 

R1#debug ip routing

 

IP routing debugging is on

 

R1#

 

*Mar  1 00:47:12.355: RT: NET-RED 0.0.0.0/0

 

R1#

 

*Mar  1 00:48:12.359: RT: NET-RED 0.0.0.0/0

 

R1#

 

*Mar  1 00:49:12.363: RT: NET-RED 0.0.0.0/0

 

R1#

 

*Mar  1 00:50:12.367: RT: NET-RED 0.0.0.0/0

 

R1#

 

*Mar  1 00:51:12.371: RT: NET-RED 0.0.0.0/0

 

R1#

 

*Mar  1 00:51:47.735: %TRACKING-5-STATE: 1 rtr 11 reachability Up->Down

 

*Mar  1 00:51:47.739: RT: del 0.0.0.0 via 209.165.201.1, static metric [2/0]

 

*Mar  1 00:51:47.743: RT: delete network route to 0.0.0.0

 

*Mar  1 00:51:47.743: RT: NET-RED 0.0.0.0/0

 

*Mar  1 00:51:47.747: RT: NET-RED 0.0.0.0/0

 

*Mar  1 00:51:47.751: RT: SET_LAST_RDB for 0.0.0.0/0

 

  NEW rdb: via 209.165.202.129

 

 

 

*Mar  1 00:51:47.755: RT: add 0.0.0.0/0 via 209.165.202.129, static metric [3/0]

 

*Mar  1 00:51:47.755: RT: NET-RED 0.0.0.0/0

 

*Mar  1 00:51:47.759: RT: default path is now 0.0.0.0 via 209.165.202.129

 

*Mar  1 00:51:47.763: RT: new default network 0.0.0.0

 

*Mar  1 00:51:47.763: RT: NET-RED 0.0.0.0/0

 

R1#

 

R1#sh ip route

 

Gateway of last resort is 209.165.202.129 to network 0.0.0.0

 

 

 

     209.165.201.0/30 is subnetted, 1 subnets

 

C       209.165.201.0 is directly connected, Serial0/0

 

     209.165.202.0/30 is subnetted, 1 subnets

 

C       209.165.202.128 is directly connected, Serial0/1

 

C    192.168.1.0/24 is directly connected, Loopback0

 

S*   0.0.0.0/0 [3/0] via 209.165.202.129

 

 

 

R1#sh ip sla monitor statistics

 

Round trip time (RTT)   Index 11

 

        Latest RTT: NoConnection/Busy/Timeout

 

Latest operation start time: *00:57:43.151 UTC Fri Mar 1 2002

 

Latest operation return code: No connection

 

Number of successes: 295

 

Number of failures: 51

 

Operation time to live: Forever

 

 

 

Round trip time (RTT)   Index 22

 

        Latest RTT: 80 ms

 

Latest operation start time: *00:57:43.159 UTC Fri Mar 1 2002

 

Latest operation return code: OK

 

Number of successes: 332

 

Number of failures: 14

 

Operation time to live: Forever

 

Now it is going through secondary path:

 

R1#traceroute 209.165.200.254 source 192.168.1.1

Type escape sequence to abort.

 

Tracing the route to 209.165.200.254

 

  1 209.165.202.129 36 msec *  36 msec

 

Now reachablity to ISP1 regains link status up:

 

ISP1(config)#interface loopback 1

 

ISP1(config-if)#no shutdown

 

ISP1(config-if)#

 

*Mar  1 01:00:38.799: %LINK-3-UPDOWN: Interface Loopback1, changed state to up

 

*Mar  1 01:00:39.799: %LINEPROTO-5-UPDOWN: Line protocol on Interface Loopback1, changed state to up

R1#

 

*Mar  1 01:01:12.415: RT: NET-RED 0.0.0.0/0

 

R1#

 

*Mar  1 01:02:12.419: RT: NET-RED 0.0.0.0/0

 

R1#

 

*Mar  1 01:02:49.159: %TRACKING-5-STATE: 1 rtr 11 reachability Down->Up

 

*Mar  1 01:02:49.163: RT: closer admin distance for 0.0.0.0, flushing 1 routes

 

*Mar  1 01:02:49.167: RT: NET-RED 0.0.0.0/0

 

*Mar  1 01:02:49.167: RT: SET_LAST_RDB for 0.0.0.0/0

 

  NEW rdb: via 209.165.201.1

 

 

 

*Mar  1 01:02:49.171: RT: add 0.0.0.0/0 via 209.165.201.1, static metric [2/0]

 

*Mar  1 01:02:49.175: RT: NET-RED 0.0.0.0/0

 

*Mar  1 01:02:49.179: RT: default path is now 0.0.0.0 via 209.165.201.1

 

*Mar  1 01:02:49.179: RT: new default network 0.0.0.0

 

*Mar  1 01:02:49.183: RT: NET-RED 0.0.0.0/0

 

R1#

 

*Mar  1 01:02:54.167: RT: NET-RED 0.0.0.0/0

 

Now it is going through primary path:

 

R1#traceroute 209.165.200.254 source 192.168.1.1

Type escape sequence to abort.

 

Tracing the route to 209.165.200.254

  1 209.165.201.1 60 msec *  28 msec

 

Yes…..Successfully achieved the task: When primary goes down, branch can reach through secondary link to Web server. And when primary link gets restored, branch reaches web server through primary path.

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