This article provides information on Port-mirroring sessions on the QFX switch.

• Port mirroring copies packets entering or exiting a port or entering a VLAN and sends the copies to a local interface for local monitoring.
• QFX-3500 supports a maximum of 4 analyzer sessions, which can have a maximum 4 ingress and 4 egress input stanzas.
• If the mirroring of more than 4 interfaces is required, then multiple interfaces can be configured within one input ingress or egress stanza.

1. A maximum of 4 analyzer sessions can be allowed on QFX-3500:

   In the example below, 4 analyzer sessions (test1, test2, test3 and test4) are configured. A new analyzer session cannot be configured as the maximum of only four analyzer sessions can be configured.
   
   Instead, only 2  input ingress and 2  input egress statements are being used.

   set forwarding-options analyzer test1 input ingress interface xe-0/0/0.0
   set forwarding-options analyzer test1 output interface xe-0/0/10.0
   set forwarding-options analyzer test2 input ingress interface xe-0/0/1.0
   set forwarding-options analyzer test2 output interface xe-0/0/11.0
   set forwarding-options analyzer test3 input egress interface xe-0/0/3.0
   set forwarding-options analyzer test3 output interface xe-0/0/13.0
   set forwarding-options analyzer test4 input egress interface xe-0/0/4.0
   set forwarding-options analyzer test4 output interface xe-0/0/14.0

    

   If we try to configure another analyzer session - test 5, it will fail to commit:

   set forwarding-options analyzer test5 input ingress interface xe-0/0/5.0
   set forwarding-options analyzer test5 output interface xe-0/0/15.0
   
   root# commit
   [edit forwarding-options sampling]
   Maximum 4 port-mirroring or analyzer sessions are allowed
   error: configuration check-out failed
   

2. A maximum of 4  input egress and 4  input ingress stanzas can be configured:
   
   In the example below, 4 analyzer sessions test1, test2 , test3 and test4 are configured and four  input ingress and four  input egress stanzas have already been used.
   
   Now a fifth analyzer stanza ‘input ingress’ or ‘input egress’ cannot be configured as the limit of ‘input ingress’ and ‘egress stanza’ has already been exceeded.

   set forwarding-options analyzer test1 input ingress interface xe-0/0/0.0
   set forwarding-options analyzer test1 input egress interface xe-0/0/0.0
   set forwarding-options analyzer test1 output interface xe-0/0/10.0
   set forwarding-options analyzer test2 input ingress interface xe-0/0/1.0
   set forwarding-options analyzer test2 input egress interface xe-0/0/1.0
   set forwarding-options analyzer test2 output interface xe-0/0/11.0
   set forwarding-options analyzer test3 input ingress interface xe-0/0/2.0
   set forwarding-options analyzer test3 input egress interface xe-0/0/2.0
   set forwarding-options analyzer test3 output interface xe-0/0/12.0
   set forwarding-options analyzer test4 input ingress interface xe-0/0/4.0
   set forwarding-options analyzer test4 input egress interface xe-0/0/4.0
   set forwarding-options analyzer test4 output interface xe-0/0/14.0
   
   

   
   If we try to configure the analyzer test5, it will fail to commit:

   set forwarding-options analyzer test5 input ingress interface xe-0/0/5.0
   set forwarding-options analyzer test5 output interface xe-0/0/15.0
   
   
   root# commit
   [edit forwarding-options sampling]
   Maximum 4 port-mirroring or analyzer sessions are allowed
   error: configuration check-out failed
   

3. If we need to mirror more than four interfaces, then multiple interfaces can be configured within an input ingress or egress stanza:

   root# show forwarding-options analyzer test1
   input {
        ingress {
               interface xe-0/0/18.0;
               interface xe-0/0/19.0;
               interface xe-0/0/20.0;
               interface xe-0/0/21.0;
               interface xe-0/0/22.0;
               interface xe-0/0/23.0;
               interface xe-0/0/24.0;
               interface xe-0/0/25.0;
               interface xe-0/0/26.0;
               interface xe-0/0/27.0;
               interface xe-0/0/28.0;
               interface xe-0/0/29.0;
               interface xe-0/0/30.0;
                }
           }
   output {
         interface {
                 xe-0/0/10.0;
                   }
          }
   

• Understanding Port Mirroring