When connecting to the Internet, the CEN can provide the connectivity required to the ISP's Point of Presence (POP) facilitating any required bandwidth with the granularity, manageability, and service performance supported by Carrier Ethernet. Likewise, when a subscriber wants to connect to an application such as a VoIP gateway, this too can be delivered over Carrier Ethernet. One of the benefits to the Subscribers is that the same CEN Service Provider that provides services for corporate interconnectivity can also provide the Internet connectivity.
There are two Ethernet services that are appropriate for this application:
- EVPL – between each customer and the content provider or ISP.
- EVP-Tree – where the content provider/ISP is designated as a root and each subscriber is designated as a leaf ensuring that each subscriber's traffic cannot be seen by other subscribers.
The EVPL is simpler from an implementation point of view, but has scalability issues, requiring many EVPLs. Also, the bandwidth is not shared between subscribers, which may be a problem for large deployments in view of the fact that Internet access is often bursty and used at different times of the day by different subscribers.
In the following example an ISP named Turbo 2000 Internet Access Inc. is connected to three enterprises for Internet Access. Each customer connects to the ISP's POP using EVPL with CE-VLAN ID of 2000. This enables the customer to use the same UNI port for other services (e.g. Disaster Recovery, L2VPN, etc.) using different CE-VLAN ID(s). See diagram at right.
In this example, assume that Customer 1 has purchased a 300 Mbps downlink service and 100 Mbps uplink service for connecting to the ISP over an unprotected UNI that will be used for another service too. The service has a single CoS, with the following performance objectives measured over a 1 hour period:
- Frame loss ratio = 0.1%
- One-Way Mean Frame Delay = 30 msec
The appropriate Service Attributes for Customer 1 are:
UNI Attributes
Uni Service Attribute | Recommended Value |
---|---|
Speed | 1 Gbps |
Service Multiplexing | Yes |
Bundling | No (only VLAN 2000 is mapped to the EVPL). COuld be Yes if other services require bundling |
All to One Bundling | No |
CE-VLAN ID for untagged and Priority Tagged frames | Any value that fits other services. Untagged frames must not be sent to the ISP POP |
Maximum Number of EVC | >=1 depends on customer's need |
Ingress BWP per UNI | No (Ingress BWP will be specified per EVC) |
Egress BWP per UNI | No |
L2CP Processing | Discard all L2CPs |
UNI per EVC Attributes
EVC per Uni Service Attribute | Recommended Value |
---|---|
CE-VLAN ID / EVC Map | Point to Point |
Ingress Bandwidth Profile per EVC | CIR=100 Mbps, CBS=50,0000 bytes EIR=0, EBS=) CF=0, CM=0 Note: The ingress BWP per EVC at customer 1 affects the uplink BW. The downlink BW is enforced by a similar ingress BWP per EVC on ISP POP |
Ingress Bandwidth Profile per CoS ID | Not specified |
Egress Bandwidth Profile per EVC | Not specified |
Egress Profile per CoS ID | Not specified |
EVC Attributes
EVC Service Attribute | Recommended Value |
---|---|
EVC Type | Point to Point |
UNI List | Customer 1 UNI Root ISP POP Root |
EVC MTU Size | 1522 |
CE VLAN ID Preservation | NO, VLAN is translated towards the ISP POP and has no significance |
CE VLAN CoS Preservation | No |
Unicast Service frame Delivery | Deliver unconditionally |
Multicast Service frame Delivery | Deliver unconditionally |
Broadcast Service frame Delivery | Deliver unconditionally |
L2CP Processing | Discard all L2CPs |
EVC Performance | Frame Loss ratio 0.1% One-Way Mean Frame Delay 30 msec |
DRAFT