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!

[Alexandr_P]

There is no VMAN configured on this X450a.

(Q-in-Q makes uplink ISP operator, so all packets received by this switch are with 1 tag)

(what reason for #sh version here?)

# sh ports 22 information detail
Port:   22

........
         VLAN cfg:
                  Name: YYY-devlan, 802.1Q Tag = 4052, MAC-limit =
No-limit, Virtual router:   VR-Default
                  Name: YYY-ctrl, 802.1Q Tag = 3556, MAC-limit =
No-limit, Virtual router:   VR-Default

Tnank you!

[Miguel-Angel_RO]

Alexandr,

We miss a piece somewhere…

I suppose you configured vman for the QinQ.

Could you give the output of the following commands? (Some of them can be wrong, I don’t have an Exos to test them for the moment:

• show vman
• show vman <vman name>
• show config | include vman
• show ports 22,23 information detail
• show version

[Alexandr_P]

Hello, Miguel!

As you can see, in this switch, it’s 2 directions - to port 22 and 23

#
# 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

And through other channel (port 23) CFM frames are normally tagged:

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

But through initial channel (port 22) CFM frames untagged:

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

Thank you!

[Miguel-Angel_RO]

Alexandr,

I’ve been looking for a doc describing better the CFM and this one is quite explicit: https://www.alliedtelesis.com/sites/default/files/documents/feature-guides/cfm_feature_overview_guid...

There is probably an issue in the CFM config. Sending it as untag means Link level.

You should double check the configs on the X460, X450 and  BD8810. On CFM level and on ports level.

Mig

[Alexandr_P]

Miguel!
 

Earlier ERPS was used. Now ERPS is deleted, so only CFM.

But your link still isn’t answer question - why CFM CCMs are untagged?

Your link is about “Dynamic creation of CFM to work with ERPS”. But in our case we manually create CFM and as you can sse CCMs is generated.

Thank you!