This article provides information on querying how many routes are present in switch hardware (TCAM)
Sometime during the migration customer may need to check the available space in hardware before importing the new routes or adding new hosts.
We can lookup how many routing TCAM entries are programmed in PFE through the below command: <o:p>
root@EX4500> start shell <o:p>
root@EX4500:RE:0% cprod -A fpc0 -c "show route ip table" <o:p>
<o:p>
We have performed the below test on EX4500 running on 12.2R2 . <o:p>
root@EX4500> show route summary <o:p>
Router ID: 10.230.205.130 <o:p>
inet.0: 2 destinations, 2 routes (2 active, 0 holddown , 0 hidden) <o:p>
Direct: 1 routes , 1 active <o:p>
Local: 1 routes, 1 active <o:p>
root@EX4500> show route forwarding-table summary <o:p>
Routing table: default.inet <o:p>
Internet: <o:p>
perm : 5 routes <o:p>
intf : 2 routes <o:p>
dest : 3 routes <o:p>
Routing table: __ master.anon__.inet <o:p>
Routing table: default.iso <o:p>
-------- snip ------ <o:p>
Protocol: IPv4 <o:p>
Table Name Table Index ( lrid ) # of Routes Bytes FRRP TID <o:p>
----------------------------------------------------------------------------------------------- <o:p>
__juniper_private1__.1 1 (0 ) 8 1180 low ---- <o:p>
__juniper_private2__.2 2 (0 ) 5 736 low ---- <o:p>
__master.anon__.3 3 (0 ) 5 736 low ---- <o:p>
default.0 0 (0 ) 9 1328 low ---- <o:p>
inet.0: 501 destinations, 501 routes (501 active, 0 holddown , 0 hidden) <o:p>
Static : 499 routes, 499 active <o:p>
user : 499 routes <o:p>
dest : 4 routes <o:p>
---------- snip -------- <o:p>
default.0 0 (0 ) 508 75328 low ---- <o:p>
Static: 499 routes, 499 active <o:p>
dest : 204 routes <o:p>
---- snip ------- <o:p>
BSD platform (MPC 8544 processor, 48MB memory, 0KB flash) <o:p>
default.0 0 (0 ) 709 100044 low ---- <o:p>
So, Host routes (ARP) and network routes share the same space in PFE. <o:p>
For example <o:p>
For EX4500 : Max number of IPv4 unicast routes in hardware: 10K. www.juniper.net/us/en/local/pdf/datasheets/1000322-en.pdf <o:p>
If System (EX4500) has learnt 8K ARP entries, those 8k host routes will be installed in PFE. <o:p>
Now the switch can only install remaining 2K IPv4 network routes. <o:p>
If routing TCAM entry exceeds route table limit, then no new host (ARP ) or network route will be installed in TCAM. <o:p>
The traffic using new routes will not be routed by the switches and will get dropped. <o:p>