CFM CCM tagging issue

[Alexandr_P]

Hello, colleagues!
 

Please give advice which way to look.

Scheme below:

X460G2 ↔ BD8810 ↔ X450a

X450a confgured with CFM, VLAN with CFM is tagged, but switch send CFM CCMs as untagged. Why so?

Below traces from BD8810 (there is traffic is double tagged - QinQ) - tcpdump -i eth2 -nn -e ether host 00:04:96:27:a9:b0

For example, ARP is normal (tagged with ID 3556)

18:44:10.774613 00:04:96:27:a9:b0 > ff:ff:ff:ff:ff:ff, ethertype 802.1Q (0x8100), length 68: vlan 1037, p 0, ethertype 802.1Q, vlan 3556, p 0, ethertype ARP, Request who-has          5.5.11.3 tell 5.5.11.1, length 46

But CFM CCM is untagged (only with second tag 1037)

18:44:11.436169 00:04:96:27:a9:b0 > 01:80:c2:00:00:33, ethertype 802.1Q (0x8100), length 101: vlan 1037, p 0, ethertype CFM, CFMv0 Continouity Check Message, MD Level     3, length 83

Config from X450a

create vlan "Q-in-Q_XXX"
configure vlan Q-in-Q_XXX tag 1037
create vlan "YYY-ctrl"
configure vlan YYY-ctrl tag 3556

……

configure vlan YYY-ctrl add ports 22-23 tagged

configure vlan YYY-ctrl ipaddress 5.5.11.1 255.255.255.0

……

#
# Module dot1ag configuration.
#
create cfm domain string "erps_rings" md-level 3
configure cfm domain "erps_rings" add association string "YYY" vlan "YYY-ctrl"
configure cfm domain "erps_rings" association "YYY" ports 22 add end-point down 6
configure cfm domain "erps_rings" association "YYY" ports 23 add end-point down 5
configure cfm domain "erps_rings" association "YYY" ports 23 end-point down add group "erpsYYYMain"
configure cfm domain "erps_rings" association "YYY" ports 22 end-point down add group "erpsYYYSlave"
configure cfm group "erpsYYYMain" add rmep 7
configure cfm group "erpsYYYSlave" add rmep 8

# sh vlan YYY-ctrl
VLAN Interface with name YYY-ctrl created by user
    Admin State:         Enabled     Tagging:   802.1Q Tag 3556 
    Description:         None
    Virtual router:      VR-Default
    IPv4 Forwarding:     Disabled
    IPv4 MC Forwarding:  Disabled
    Primary IP:          5.5.11.1/24
    IPv6 Forwarding:     Disabled
    IPv6 MC Forwarding:  Disabled
    IPv6:                None
    STPD:                None
    Protocol:            Match all unfiltered protocols
    Loopback:            Disabled
    NetLogin:            Disabled
    OpenFlow:            Disabled
    QosProfile:          None configured
    Egress Rate Limit Designated Port: None configured
    Flood Rate Limit QosProfile:       None configured
    Ports:   2.           (Number of active ports=2)
       Tag:       *22,    *23

Thank you!

[Miguel-Angel_RO]

Alexandr,

Are you using ERPS in your config?

If so, there are additional commands for this kind of config like here: https://gtacknowledge.extremenetworks.com/articles/Solution/Discontinue-CFM-dynamic-creation-does-no...

Mig

[Alexandr_P]

also you can see below picture with double tagged CFM CCM

Thank you!

[Alexandr_P]

Below CFM packet received from other direction (second tag stripped) and we can see right tag (vlan YYY-ctrl - tag 3556 😞

16:04:02.273002 00:04:96:27:a9:b0 > 01:80:c2:00:00:33, ethertype 802.1Q (0x8100), length 101: vlan 3556, p 7, ethertype CFM, CFMv0 Continouity Check Message, MD Level 3, length 83

Through initial issued direction (through QinQ - where second tag 1037 is stripped) - we can’t see any tags:

16:08:25.251914 00:04:96:27:a9:b0 > 01:80:c2:00:00:33, ethertype CFM (0x8902), length 97: CFMv0 Continouity Check Message, MD Level 3, length 83

Also, below example right CFM CCM with 2 tags:

15:51:12.264262 00:04:96:27:99:02 > 01:80:c2:00:00:33, ethertype 802.1Q (0x8100), length 105: vlan 1198, p 0, ethertype 802.1Q, vlan 1352,                                                 p 7, ethertype CFM, CFMv0 Continouity Check Message, MD Level 3, length 83

Thank you!

[Miguel-Angel_RO]

Alexandr,

CFM has a specific ethertype, you cannot tag it as it is not 802.1Q (tagged frame):

For example, ARP is normal (tagged with ID 3556)

18:44:10.774613 00:04:96:27:a9:b0 > ff:ff:ff:ff:ff:ff, ethertype 802.1Q (0x8100), length 68: vlan 1037, p 0, ethertype 802.1Q, vlan 3556, p 0, ethertype ARP, Request who-has          5.5.11.3 tell 5.5.11.1, length 46

But CFM CCM is untagged (only with second tag 1037)

18:44:11.436169 00:04:96:27:a9:b0 > 01:80:c2:00:00:33, ethertype 802.1Q (0x8100), length 101: vlan 1037, p 0, ethertype CFM, CFMv0 Continouity Check Message, MD Level     3, length 83

Mig