::::::::Notes::::::::: (802.1q Tunneling/QinQ Tunneling)(Used for Metro-Ethernet Networks/Layer 2 VPN) 1.Layer 2 VPN over switched ethernet network (similar to lightweight version of MPLS L2VPN)(Any transport over MPLS(AToM)/Virtual Private Lan Services(VPLS) feature) 2.SP's PE adds additional 802.1q tag to all frames received from CE (called 'metro tag' or 'QinQ)(transport frames over the provider network) 3.PE assigns all CE facing ports to the same VLAN (one VLAN per customer in P network) 4.deplolyed in metro-ethernet environment (transparent L2 trunk through the services provider switches) 5.Can't be dynamically negotiated 6.cusctomer's traffic is segmented from the provider's traffic (metro tag added and removed from end to end) 7.core of the service provider will know about the mac addresses of customers 8.once configured CE switches will be able to see each other and won't see any PE switches as cdp neighbors. (802.1q Tunneling Design Issues) 1.Assumes layer 2 network end-to-end ->PE-P-PE links must all run layer 2 trunking (implies scalability issues(ethernet inside and ethernet). If SP network large they don't want to run layer2 everywhere, which is why MPLS layer2 VPNs over 802.1q tunnel. So both L2 and L3 services while tunneling the traffic inside IP in the core) 2.Additional tags increase payload size (MTU issues) ->4 bytes per tag ->Potential to exceed MTU of transit path ->Ethernet doesn't support fragmentation ->PE should set the MTU higher than 1500 i.e 1504 to allow the 4 byte metro-tag (it's important to do this) 3.Loss of control plane signaling for CE devices ->CDP, VTP, STP, etc. dropped by PE (as these are encoded with special source and destination mac addresses and by default these can not be inserted into the CAM table)(which is why Switch disables cdp by default) (Layer 2 Protocol Tunneling) 1.Used to tunnel Layer 2 control plane protocols between ports ->typically used with 802.1q tunnel 2.Supports for CDP,VTP,STP,PAgP,LACP,UDLD. (Etherchannel over 802.1 Tunnels) 1.CE can support aggregation of CE-PE links(e.g. 2xGigE per customer site) 2.Etherchannel always has to be point-to-point (As many metro tags need as many links/ports being aggregated)(Implies one metro tag per PE-CE link) 3.PE can tunnel negotiate aswell 4.If a frame leaves one CE and does not reach exactly the same to other CE end then you have caused layer 2 loops
13
Embed
Notes::::::::: (802.1q Tunneling/QinQ Tunneling)(Used for ... · (802.1q Tunneling/QinQ Tunneling)(Used for Metro-Ethernet Networks/Layer 2 VPN) 1.Layer 2 VPN over switched ethernet
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
::::::::Notes:::::::::
(802.1q Tunneling/QinQ Tunneling)(Used for Metro-Ethernet Networks/Layer
2 VPN)
1.Layer 2 VPN over switched ethernet network (similar to lightweight
version of MPLS L2VPN)(Any transport over MPLS(AToM)/Virtual Private Lan
Services(VPLS) feature)
2.SP's PE adds additional 802.1q tag to all frames received from CE (called
'metro tag' or 'QinQ)(transport frames over the provider network)
3.PE assigns all CE facing ports to the same VLAN (one VLAN per customer
in P network)
4.deplolyed in metro-ethernet environment (transparent L2 trunk through
the services provider switches)
5.Can't be dynamically negotiated
6.cusctomer's traffic is segmented from the provider's traffic (metro tag
added and removed from end to end)
7.core of the service provider will know about the mac addresses of
customers
8.once configured CE switches will be able to see each other and won't see
any PE switches as cdp neighbors.
(802.1q Tunneling Design Issues)
1.Assumes layer 2 network end-to-end
->PE-P-PE links must all run layer 2 trunking
(implies scalability issues(ethernet inside and ethernet). If SP network
large they don't want to run layer2 everywhere, which is why MPLS layer2
VPNs over 802.1q tunnel. So both L2 and L3 services while tunneling the