Support Support Downloads Knowledge Base Case Manager My Juniper Community

Knowledge Base

Search our Knowledge Base sites to find answers to your questions.

Ask All Knowledge Base Sites All Knowledge Base Sites JunosE Defect (KA)Knowledge BaseSecurity AdvisoriesTechnical BulletinsTechnotes Sign in to display secure content and recently viewed articles

How to check IP route table utilization on the hardware (TCAM).

0

0

Article ID: KB27700 KB Last Updated: 19 Jun 2013Version: 1.0
Summary:
This article provides information on querying how many routes are present in switch hardware (TCAM)

Symptoms:
Sometime during the migration customer may need to check the available space in hardware before importing the new routes or adding new hosts.

Cause:

Solution:

We can lookup how many routing TCAM entries are programmed in PFE through the below command:

root@EX4500> start shell

root@EX4500:RE:0% cprod -A fpc0 -c "show route ip table"

 

Example:

 

We have performed the below test on EX4500 running on 12.2R2 .

 

Ø  When no network routes are installed on the box.

root@EX4500> show route summary

Router ID: 10.230.205.130

 

inet.0: 2 destinations, 2 routes (2 active, 0 holddown, 0 hidden)

              Direct:      1 routes,      1 active

               Local:      1 routes,      1 active

 

root@EX4500> show route forwarding-table summary

Routing table: default.inet

Internet:

         perm:          5 routes

         intf:          2 routes

         dest:          3 routes

 

Routing table: __master.anon__.inet

Internet:

         perm:          5 routes

 

Routing table: default.iso

--------snip------

 

 

root@EX4500> start shell

root@EX4500:RE:0% cprod -A fpc0 -c "show route ip table"

Protocol: IPv4

    Table Name                       Table Index (lrid ) # of Routes  Bytes        FRRP TID        

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

    __juniper_private1__.1           1           (0    ) 8            1180         low ----

    __juniper_private2__.2           2           (0    ) 5            736          low ----

    __master.anon__.3                3           (0    ) 5            736          low ----

    default.0                        0           (0    ) 9            1328         low ----

 

Ø  When we configured 499 static routes.

 

root@EX4500> show route summary                    

Router ID: 10.230.205.130

 

inet.0: 501 destinations, 501 routes (501 active, 0 holddown, 0 hidden)

              Direct:      1 routes,      1 active

               Local:      1 routes,      1 active

              Static:    499 routes,    499 active

 

root@EX4500> show route forwarding-table summary   

Routing table: default.inet

Internet:

         user:         499 routes

         perm:          5 routes

         intf:          2 routes

         dest:          4 routes

 

Routing table: __master.anon__.inet

Internet:

         perm:          5 routes

----------snip--------

 

                                       

 

root@EX4500> start shell

root@EX4500:RE:0% cprod -A fpc0 -c "show route ip table"

Protocol: IPv4

    Table Name                       Table Index (lrid ) # of Routes  Bytes        FRRP TID        

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

    __juniper_private1__.1           1           (0    ) 8            1180         low ----

    __juniper_private2__.2           2           (0    ) 5            736          low ----

    __master.anon__.3                3           (0    ) 5            736          low ----

    default.0                        0           (0    ) 508          75328        low ----

 

 

Ø  When box learnt 200 new ARP entries.

 root@EX4500> show route summary

Router ID: 10.230.205.130

 

inet.0: 501 destinations, 501 routes (501 active, 0 holddown, 0 hidden)

              Direct:      1 routes,      1 active

               Local:      1 routes,      1 active

              Static:    499 routes,    499 active

 

root@EX4500> show route forwarding-table summary

Routing table: default.inet

Internet:

         user:         499 routes

         perm:          5 routes

         intf:          2 routes

         dest:         204 routes

 

Routing table: __master.anon__.inet

Internet:

         perm:          5 routes

----snip-------

 

                                       

root@EX4500> start shell

root@EX4500:RE:0% cprod -A fpc0 -c "show route ip table"

 

BSD platform (MPC 8544 processor, 48MB memory, 0KB flash)

 

Protocol: IPv4

    Table Name                       Table Index (lrid ) # of Routes  Bytes        FRRP TID        

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

    __juniper_private1__.1           1           (0    ) 8            1180         low ----

    __juniper_private2__.2           2           (0    ) 5            736          low ----

    __master.anon__.3                3           (0    ) 5            736          low ----

    default.0                        0           (0    ) 709          100044       low ----

 

 

So, Host routes (ARP) and network routes share the same space in PFE.

For example

 

For EX4500 : Max number of IPv4 unicast routes in hardware: 10K.
 www.juniper.net/us/en/local/pdf/datasheets/1000322-en.pdf

If System (EX4500) has learnt 8K ARP entries, those 8k host routes will be installed in PFE.

Now the switch can only install remaining 2K IPv4 network routes.

 

If routing TCAM entry exceeds route table limit, then no new host (ARP) or network route will be installed in TCAM.

 

The traffic using new routes will not be routed by the switches and will get dropped.


Related Links

Comment on this article > Affected Products Browse the Knowledge Base for more articles related to these product categories. Select a category to begin.

Getting Up and Running with Junos

Getting Up and Running with Junos Security Alerts and Vulnerabilities Product Alerts and Software Release Notices Problem Report (PR) Search Tool EOL Notices and Bulletins JTAC User Guide Customer Care User Guide Pathfinder SRX High Availability Configurator SRX VPN Configurator Training Courses and Videos End User Licence Agreement Global Search