Everflow mirror session

Restriction:

• SONiC Everflow is similar to Cisco ERSPAN. 
• SONiC does NOT support Local SPAN and Remote SPAN. (Definitions of SPAN/RSPAN /ERSPAN, please refer to Cisco Types of SPAN)
• Everflow supports mirror only ingress traffic of source interface. Because SONiC ACL supports only ingress direction(refer to this article). 
• There is no SONiC command for add ACL Table for type MIRROR. (refer to this article)

Reference model:

• Switch model name: AS7816-64X
• Edgecore SONiC version: SONiC.Edgecore-SONiC_20200116_051623_ec201904_128

Example 1. Basic Everflow configuration

Procedure :

Step 1. Configure Switch IP address (refer to this article)

i.g 192.168.1.1/24 on Ethernet0

admin@sonic:~$ sudo config interface ip add Ethernet0 192.168.1.1/24

Step 2. Create a mirror session to specify source and destination IP address.

This command is used to add or remove mirroring sessions. Mirror session is identified by "session_name".

config mirror_session add [OPTIONS] <session_name> <src_ip> <dst_ip> <dscp> <ttl> [gre_type] [queue]

 Note: session_name, src_ip, dst_ip, dscp, ttl are required for adding a new session.    are_type and queue are optional.

admin@sonic:~$ sudo config mirror_session add ts1_everflow 192.168.1.1 192.168.3.35 63 255

Caution: src_ip is switch IP address. (refer to Step 1. Configure switch IP address)

Step 3. Check mirror_session by SONiC commands

admin@sonic:~$ show mirror_session
Name Status SRC IP DST IP GRE DSCP TTL Queue
------------ -------- ----------- ------------ ----- ------ ----- -------
ts1_everflow error 192.168.1.1 192.168.3.35 63 255

Caution/known issue: status of mirror session always display error. 

This is a known issue and it is a display issue only. It will be fixed in new version.

https://github.com/Azure/sonic-buildimage/issues/3188

Step 4. Save above settings to /etc/sonic/config_db.json, since we will edit /etc/sonic/config_db.json on the following steps. 

admin@sonic:~$ sudo config save -y

Step 5. Create ACL table and rules for traffic classification. (How to add ACL table and rules? Please refer to this article)

admin@sonic:/etc/sonic$ sudo vi config_db.json
{
    omitted...
    "ACL_TABLE": {
        "ACL_Mirror": {
            "policy_desc": "mirror",
            "type": "MIRROR",
            "stage": "ingress",
            "ports": ["Ethernet1"]
        }
    },
    "ACL_RULE": {
        "ACL_Mirror|ACE_Mirror": {
            "PRIORITY": "55",
            "IP_TYPE": "ipv4any",
            "MIRROR_ACTION": "ts1_everflow"
        }
    },
    omitted...
}

Note:

• The value of ACL type must be MIRROR
• The value of MIRROR_ACTION is the name of mirror session

Steps 6. Reload config or Reboot the switch

admin@sonic:~$ sudo config reload -y

Step 7. Check ACL table and rules

admin@sonic:~$ show acl table
Name Type Binding Description
---------- ------ --------- -------------
ACL_Mirror MIRROR Ethernet1 mirror
admin@sonic:~$ show acl rule
Table Rule Priority Action Match
---------- ---------- ---------- -------------------- ----------------
ACL_Mirror ACE_Mirror 55 MIRROR: ts1_everflow IP_TYPE: ipv4any

Caution:  Have to make sure IP connectivity works properly between the switch and remote server. Otherwise, 

Steps 7. Check the arp of monitor server is learned on arp table.

admin@sonic:~$ show arp
Address MacAddress Iface Vlan
------------ ----------------- ---------- ------
192.168.3.35 8c:ea:1b:30:da:4a Ethernet16 -
Total number of entries 1

Caution: Before switch learn the arp of monitor device to arp table, the ERSPAN won't work.

ACL Table example: Classify LLDP(0x88CC) and LACP(0x8809) packets

"ETHER_TYPE": "0x88cc" for LLDP

"ETHER_TYPE": "0x8809" for LACP

/etc/sonic/config_db.json

{
    omitted...
    "ACL_TABLE": {
        "ACL_Mirror": {
            "policy_desc": "mirror",
            "type": "MIRROR",
            "stage": "ingress",
            "ports": ["Ethernet8"]
        }
    },
    "ACL_RULE": {
        "ACL_Mirror|ACE_Mirror1": {
            "PRIORITY": "55",
            "ETHER_TYPE": "0x88cc",
            "MIRROR_ACTION": "ts1_everflow"
        },
        "ACL_Mirror|ACE_Mirror2": {
            "PRIORITY": "54",
            "ETHER_TYPE": "0x8809",
            "MIRROR_ACTION": "ts1_everflow"
        }, 
    },
    omitted...
}