Cisco IOS IP SLA

The Cisco IOS IP Service Level Agreements (SLAs) is a core part of the Cisco IOS software portfolio, which allows Cisco customers to analyze IP service levels for IP applications and services, to increase productivity, to lower operational costs, and to reduce the frequency of network outages.

The Cisco IOS IP SLAs uses active traffic monitoring—the generation of traffic in a continuous, reliable, and predictable manner—for measuring network performance. Using Cisco IOS IP SLA, service provider customers can measure and provide SLAs, and enterprise customers can verify service levels, verify out sourced SLAs, and understand network performance.

The Cisco IOS IP SLAs can perform network assessments, verify quality of service (QoS), ease the deployment of new services, and assist administrators with network troubleshooting.

The Cisco IOS IP SLAs can be accessed using the Cisco IOS CLI or Simple Network Management Protocol (SNMP) through the Cisco Round-Trip Time Monitor (RTTMON) and syslog Management Information Bases (MIBs).

For detailed information on Cisco IOS IP SLA features, see IP SLAs Configuration Guide, Cisco IOS Release 15.1S.


Note
Cisco IOS IP SLA for VoIP, ICMP Jitter, Gatekeeper and Data Link Switching Plus (DLSw+) features are not supported in Cisco ASR 901 router.

Configuring IPSLA Path Discovery

The LSP path discovery (LPD) feature allows the IP SLA MPLS LSP to automatically discover all the active paths to the forwarding equivalence class (FEC), and configure LSP ping and traceroute operations across various paths between the provide edge (PE) devices.

Complete the following steps to configure IPSLA path discovery in a typical VPN setup for MPLS LPD operation:

Procedure

  Command or Action Purpose

Step 1

enable

Example:


Router> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:


Router# configure terminal

Enters global configuration mode.

Step 3

mpls discoveryvpnnext-hop

Example:


Router(config)# mpls discovery vpn next-hop

(Optional) Enables the MPLS VPN next hop neighbor discovery process.

Note

 
This command is automatically enabled when the auto ip sla mpls-lsp-monitor command is entered.

Step 4

mpls discovery vpn interval seconds

Example:


Router(config)# mpls discovery vpn interval 120

(Optional) Specifies the time interval at which routing entries that are no longer valid are removed from the next hop neighbor discovery database of an MPLS VPN.

Step 5

auto ip slampls-lsp-monitor operation-number

Example:


Router(config)# auto ip sla mpls-lsp-monitor 1

Begins configuration for an LSP Health Monitor operation and enters auto IP SLA MPLS configuration mode.

Step 6

type echo ipsla-vrf-all

Example:


Router(config-auto-ip-sla-mpls)# type echo ipsla-vrf-all

Enters MPLS parameters configuration submode and allows the user to configure the parameters for an IP SLAs LSP ping operation using the LSP Health Monitor.

What to do next

Configuration Parameters 


Router(config)#auto ip sla mpls-lsp-monitor 1
 
Router(config-auto-ip-sla-mpls)#?
Auto IP SLAs MPLS LSP Monitor entry configuration commands:
 exit  Exit IP SLAs MPLSLM configuration
 type  Type of entry
Router(config-auto-ip-sla-mpls)#type ?
 echo      Perform MPLS LSP Ping operation
 pathEcho  Perform MPLS LSP Trace operation
Router(config-auto-ip-sla-mpls)#type pathEcho ?
 ipsla-vrf-all  Configure IP SLAs MPLS LSP Monitor for all VPNs
 vrf            vrf Name

Following parameters can be configured in the auto-ip-sla-mpls-params mode: 


Router(config-auto-ip-sla-mpls)#type echo ipsla-vrf-all 
Router(config-auto-ip-sla-mpls-params)#?
IP SLAs MPLSLM entry parameters configuration commands:
 access-list          Apply Access-List
 default              Set a command to its defaults
 delete-scan-factor   Scan Factor for automatic deletion
 exit                 Exit IP SLAs MPLSLM configuration
 exp                  EXP value
 force-explicit-null  force an explicit null label to be added
 lsp-selector         LocalHost address used to select the LSP
 no                   Negate a command or set its defaults
 path-discover        IP SLAs LSP path discover configuration
 reply-dscp-bits      DSCP bits in reply IP header
 reply-mode           Reply for LSP echo request
 request-data-size    Request data size
 scan-interval        Scan Interval for automatic discovery in minutes
 secondary-frequency  Frequency to be used if there is any violation condition
                      happens
 tag                  User defined tag
 threshold            Operation threshold in milliseconds
 timeout              Timeout of an operation
 ttl                  Time to live

Following parameters can be configured in the auto-ip-sla-mpls-lpd-params mode: 


Router(config-auto-ip-sla-mpls-params)#path-discover 
Router(config-auto-ip-sla-mpls-lpd-params)#?
IP SLAs MPLS LSP Monitor LPD configuration commands:
 default                   Set a command to its defaults
 exit                      Exit IP SLAs MPLS LSP Monitor path discover
                           configuration
 force-explicit-null       Force an explicit null label to be added
 hours-of-statistics-kept  Maximum number of statistics hour groups to capture
 interval                  Send interval between requests in msec
 lsp-selector-base         Base 127/8 address to start the tree trace
 maximum-sessions          Number of concurrent active tree trace requests
                           which can be submit at one time
 no                        Negate a command or set its defaults
 scan-period               Time period for finishing tree trace discovery in
                           minutes
 session-timeout           Timeout value for the tree trace request in seconds
 timeout                   Timeout for an MPLS Echo Request in seconds

Example for IPSLA Path Discovery


auto ip sla mpls-lsp-monitor 1
type echo ipsla-vrf-all
path-discover
auto ip sla mpls-lsp-monitor schedule 1 schedule-period 1 frequency 10 start-time now

This example shows the LPD parameter values configured: 


auto ip sla mpls-lsp-monitor 2
type echo vrf vpn1
path-discover
force-explicit-null
hours-of-statistics-kept 1
scan-period 30
lsp-selector-base 127.0.0.7
session-timeout 20
timeout 100
interval 1000
auto ip sla mpls-lsp-monitor schedule 2 schedule-period 1 frequency 10 start-time now
Router#show
 ip sla mpls-lsp-monitor summary
 
Index                    -  MPLS LSP Monitor probe index
Destination              -  Target IP address of the BGP next hop
Status                   -  LPD group status
LPD Group ID             -  Unique index to identify the LPD group
Last Operation Time      -  Last time an operation was attempted by
                            a particular probe in the LPD Group
Index  Destination     Status     LPD Group ID    Last Operation Time
1      2.2.2.2         up         100004          *20:08:01.481 UTC Tue Nov 14 2000
Router#show
 ip sla mpls-lsp-monitor neighbors
 
IP SLA MPLS LSP Monitor Database : 1
BGP Next hop 2.2.2.2 (Prefix: 2.2.2.2/32)  OK Paths: 2
  ProbeID: 100004 (pavan_1)
Router# show ip sla mpls-lsp-monitor lpd operational-state 
Entry number: 100004
MPLSLM Entry Number: 1
Target FEC Type: LDP IPv4 prefix
Target Address: 2.2.2.2
Number of Statistic Hours Kept: 2
Last time LPD Stats were reset: *18:00:57.817 UTC Sat Nov 11 2000
Traps Type: 1
Latest Path Discovery Mode: initial complete
Latest Path Discovery Start Time: *20:04:26.473 UTC Tue Nov 14 2000
Latest Path Discovery Return Code: OK
Latest Path Discovery Completion Time(ms): 40
Number of Paths Discovered: 2
Path Information :
Path   Outgoing   Lsp             Link  Conn  Adj             NextHop         Downstream  
Index  Interface  Selector        Type  Id    Addr            Addr            Label Stack     Status 
1      Vl22       127.0.0.0       90    0     22.1.1.1        22.1.1.1        29              OK
2      Vl26       127.0.0.0       90    0     26.1.1.2        26.1.1.2        21              OK
Router# show ip sla mpls-lsp-monitor configuration
 
Entry Number : 1
Modification time   : *20:19:08.233 UTC Tue Nov 14 2000
Operation Type      : echo
Vrf Name            : ipsla-vrf-all
Tag                 : 
EXP Value           : 0
Timeout(ms)         : 5000
Threshold(ms)       : 5000
Frequency(sec)      : 10
ScanInterval(min)   : 1
Delete Scan Factor  : 1
Operations List     : 100006
Schedule Period(sec): 1
Request size        : 100
Start Time          : Start Time already passed
SNMP RowStatus      : Active
TTL value           : 255
Reply Mode          : ipv4
Reply Dscp Bits     : 
Path Discover       : Enable
    Maximum sessions          : 1
    Session Timeout(seconds)  : 120
    Base LSP Selector         : 127.0.0.0
    Echo Timeout(seconds)     : 5
    Send Interval(msec)       : 1000
    Label Shimming Mode       : 
    Number of Stats Hours     : 2
    Scan Period(minutes)      : 1
[Wrap text]  [Edit this enclosure] 
Unit-test_IPSLA: Added 12/02/2011 00:05:01 by pacv 
[Unwrap text]  [Edit this enclosure] 
Unit-test_IPSLA: Added 12/02/2011 00:05:01 by pacv

Two-Way Active Measurement Protocol

Two-Way Active Measurement Protocol (TWAMP) consists of two related protocols. Use the TWAMP-Control protocol to start performance measurement sessions. You can deploy TWAMP in a simplified network architecture, with the control-client and the session-sender on one device and the server and the session-reflector on another device.

The Cisco IOS software TWAMP implementation supports a basic configuration. TWAMP Deployment shows a sample deployment.

TWAMP Architecture shows the four logical entities that comprise the TWAMP architecture.

Figure 1. TWAMP Deployment
Figure 2. TWAMP Architecture

Although each entity is separate, the protocol allows for logical merging of the roles on a single device.

Configuring TWAMP

The TWAMP server and reflector functionality are configured on the same device. This section contains the following topics:

Configuring the TWAMP Server

Complete the following steps to configure the TWAMP server:

Procedure

  Command or Action Purpose

Step 1

enable

Example:


Router> enable

Enables the privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:


Router# configure terminal

Enters the global configuration mode.

Step 3

ip sla server twamp

Example:


Router(config)# ip sla server twamp

Configures the Cisco ASR 901 router as a TWAMP server, and enters TWAMP configuration mode.

Step 4

port port-number

Example:


Router(config-twamp-srvr)# port 9000

(Optional) Specifies the port number to be used by the TWAMP server to listen for connection and control requests. The same port negotiates for the port to which performance probes are sent. The configured port should not be an IANA port or any port used by other applications. The default is port 862.

Step 5

timer inactivity seconds

Example:


Router(config-twamp-srvr)# timer inactivity 300

(Optional) Sets the maximum time, in seconds. The session can be inactive before the session ends. The range is between 1 to 6000 seconds. The default is 900 seconds.

Step 6

end

Example:


Router(config-twamp-srvr)# end

Return to privileged EXEC mode.

Configuring the TWAMP Reflector

To disable the IP SLA TWAMP server, enter the no ip sla server twamp global configuration command.

Configuring the TWAMP Reflector

The TWAMP server and reflector functionality are both configured on the same device.

Complete the following steps to configure the TWAMP reflector:

Procedure

  Command or Action Purpose

Step 1

enable

Example:


Router> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:


Router# configure terminal

Enters global configuration mode.

Step 3

ip sla server twamp

Example:


Router(config)# ip sla server twamp

Configures the switch as a TWAMP responder, and enter TWAMP configuration mode.

Step 4

timer inactivity seconds

Example:


Router(config-twamp-srvr)# timer inactivity 300

(Optional) Sets the maximum time, in seconds. The session can be inactive before the session ends. The range is between 1 to 604800 seconds. The default is 900 seconds.

Step 5

end

Example:


Router(config-twamp-srvr)# end

Return to privileged EXEC mode.

Configuration Examples for TWAMP

This section provides the following configuration examples:

Example: Configuring the Router as an IP SLA TWAMP server


Router(config)# ip sla server 
twamp 
Router(config-twamp-srvr)# port 9000

Router(config-twamp-srvr)# timer inactivity 300

Example: Configuring the Router as an IP SLA TWAMP Reflector


Router(config)# ip sla responder 
twamp

Router(config-twamp-srvr)# timeout 300