There are three attributes of a UNI that affect the type of Carrier Ethernet service(s) that can be defined at the UNI:
A UNI can be defined to terminate exactly one service or multiple Ethernet Services. If the Service Multiplexing attribute has the value YES (enabled) then multiple Ethernet Services can terminate at the UNI. If Service Multiplexing has the value NO (disabled), then only one Ethernet Service can terminate at the UNI.
If Service Multiplexing is allowed at the UNI, there needs to be a way to associate incoming frames with specific services. The MEF services use the Customer Edge VLAN ID (CE-VLAN ID) as the way to do this. The next two parameters define attributes of how the CE-VLAN IDs can be mapped to services.
If the Bundling attribute has the value YES (enabled) then multiple CE-VLAN IDs can be associated with an Ethernet Service at the UNI. If the Bundling attribute has the value No (disabled) then each Ethernet Service at the UNI can be associated with only one CE-VLAN ID.
This is a special case of bundling in which, when enabled, all CE-VLAN IDs are mapped to one Ethernet Service. If All-to-One Bundling is YES (enabled) there there can (by definition) be only one service on the UNI and it must be a Private Service. If All-to-One Bundling is NO (disabled) then there can be one or more Virtual Private Services on the UNI.
These three attributes are inter-related and the table at right explains the valid combinations:
(Service Multiplexing = YES) ↔ (All-To-One Bundling = NO)
If multiple services can terminate at the UNI then you can't have all CE-VLAN IDs mapped to a single Ethernet Service and vice versa.
(Bundling = YES) → (All-to-One Bundling = NO)
Being able to map multiple individual CE-VLAN IDs to a single service is different than mapping all CE-VLAN IDs to a single service. So these two parameters cannot both be enabled. Note that the other direction is not a requirement, i.e. if All-To-One Bundling is NO, Bundling can be YES or NO. But,
(All-to-One Bundling = YES) → (Bundling = NO)
Mapping all CE-VLAN IDs to a single service is different from being able to map multiple individual CE-VLAN IDs to a single service.
Bundling and All-to-One Bundling cannot both be YES at a UNI, but they can both be NO.
Based on the definitions and rules in the left column, here are the combinations of the three attributes.
All to One Bundling
|Yes||No||No||Multiple virtual private services allowed at the UNI with only one CE-VLAN ID mapped to each service.|
|Yes||Yes||No||Multiple virtual private services allowed at the UNI and multiple CE-VLAN IDs can be mapped to each service.|
|No||No||Yes||Single "private" service at the UNI.|
|No||Yes||No||Single virtual private service allowed at the UNI with multiple CE-VLAN IDs mapped to it.|
|No||No||No||Single virtual private service allowed at the UNI with only a single CE-VLAN ID mapped to it.|
What is the difference betweeen (No, No, Yes configuration) Single "private" service at the UNI and (No, No, No configuration) Single virtual private service allowed at the UNI with only a single CE-VLAN ID mapped to it?
May I have an example of (No, Yes, No) Single virtual private service allowed at the UNI with multiple CE-VLAN IDs mapped to it type of service?
The difference between NNY and NNN is that NNY is a private service so ALL (4094) CE-VLANs are mapped to the service and NNN is a virtual private service so only specified CE-VLANs are mapped to the service and in this case exactly one – for example, CE-VLAN 18.
NYN is like NNN except that multiple CE-VLANs can be mapped to the service – for example, CE-VLANs 18, 21, 27
In other words:
In a NNY configuration, any CE-VLAN tagged frame will be passed into Ethernet Service.
In a NYN configuration, only the frames with the specified CE-VLAN tags will be passed to the Ethernet Service. Frames with CE-VLAN tags different from the specified ones will be dropped.
Finally, if instead of allowing multiple CE-VLAN tags to be passed into the Ethernet Service, you could specify only one CE-VLAN tag to be passed into the Ethernet Service. Everything else will be droped. That is the NNN configuration.