Ethernet Service Networking. Transparent Transmission. Shared VCTRUNK. Ingress/Egress. Resilient Packet Ring, страница 8

4. Summary

Under the same QoS level, the RPR processing board also supports the same EVPL service of the Ethernet service processing board, but it does not support the private line service that occupies channels exclusively.

The VIP private line service has plenty and dispersive access points and requires low bandwidth, so the single ring architecture of RPR is not suitable for private line service. In addition, the private line service is of high priority and requires bandwidth strictly, which cannot realize the advantages of RPR, such as fairness and statistical multiplexing. Therefore, the Ethernet service processing board is more applicable to this kind of service.

4.5.2 EVPLAN

1. Service Requirement

The access services of communities are from city 2, 3 and 4, each of which can access the other two. Services from these three cities are converged in city 1 and then interconnected with the Ethernet equipment at the backbone layer through a GE interface. So are the public access services from city 2, 3 and 4. The Ethernet equipment in city 1 supports MPLS. The community access services and public access services are required to be isolated from each other, yet sharing 2 x VC-4 bandwidth. These services are protected at the Ethernet layer with the switching time less than 50ms.

The community access services include video and VPN service. The public access services include IP phone and services in cyber cafes. These services are of different priorities. For example, the network must assure the bandwidth and latency jitter for video and IP phone, and assure bandwidth for VPN. The network provides best effort delivery for services from cyber cafes.

Isolate different services from the same place with the VLAN ID.

2. Application

Service requirements:

n Multi-point dynamic sharing

n Service isolation

n Ethernet-layer protection

n Provide different services according to the service type

To meet these requirements, use a RPR to carry the EVPLAN service.

In Figure 4-9, NE1–NE4 are all OptiX OSN 3500s and are equipped with the resilient packet ring processing board to support EVPLAN service.

Figure 4-9 EVPLAN application on RPR

3. Implementation

Implementation	Service type: EVPLAN VB + VLAN route + VMAN route Use the virtual MAN (VMAN) label to divide the user domain into red and blue, and use the VLAN ID on VB to further identify users. The VB ports in different VMAN domains may have the same VLAN ID, as shown below. There are two VMAN domains corresponding to two EVPLAN services on the RPR. The red domain is VMAN2 and the blue domain is VMAN1. The VB1 of EVPLAN1 is in VMAN1 and the VB2 of EVPLAN2 is in VMAN2. Each VB may include more than one VLAN, such as VLAN ID: 1 and VLAN ID: 2. The PRP1 port belongs to all VMAN domains. Services from each node access the internet through NE1. On RPR, you can set traffic priority for each port, thus providing different services according to the traffic type.
Hardware configuration	Configure an EMR0 board in NE1 to converge services and to interconnect with the Ethernet equipment at upper layer through a GE port. Configure an EMR0 in NE2 to access public services and community FE services. Configure an EMR0 in NE3 to access public services and community FE services. Configure an EMR0 in NE4 to access public services and community FE services. Caution: The board configured in each node of the RPR should be the same RPR processing board.
Hardware configuration	For slots of EMR0, refer to “Appendix A Network Configuration Requirements”. & Note: EMR0 can be inserted in all slots with the interface board. However, it supports 8 x VC-4 bandwidth only in the 2.5 Gbit/s slot. Its maximum bandwidth is 4 x VC-4 when seating in a 1.25 Gbit/s slot.
Service route	NE1	Public	VB1 [MAC1 (VMAN label 1), RPR1 (VMAN label 1)] VLAN ID: 1 filtering table [MAC1, RPR1] VLAN ID: 2 filtering table [MAC1, RPR1]
		Community	VB2 [MAC1 (VMAN label 2), RPR1 (VMAN label 2)] VLAN ID: 1 filtering table [MAC1, RPR1] VLAN ID: 2 filtering table [MAC1, RPR1]
	NE2	Public	VB1 [MAC2, RPR1 (VMAN label 1)] VLAN ID: 1 filtering table [MAC2, RPR1] VLAN ID: 2 filtering table [MAC2, RPR1]
		Community	VB2 [MAC3, RPR1 (VMAN label 2)] VLAN ID: 1 filtering table [MAC3, RPR1]
	NE3	Public	VB1 [MAC2, RPR1 (VMAN label 1)] VLAN ID: 1 filtering table [MAC2, RPR1]
		Community	VB2 [MAC3, RPR1 (VMAN label 2)] VLAN ID: 1 filtering table [MAC3, RPR1] VLAN ID: 2 filtering table [MAC3, RPR1]
	NE4	Public	VB1 [MAC2, RPR1 (VMAN label 1)] VLAN ID: 1 filtering table [MAC2, RPR1] VLAN ID: 2 filtering table [MAC2, RPR1]
		Community	VB2 [MAC3, RPR1 (VMAN label 2)] VLAN ID: 1 filtering table [MAC3, RPR1]
	The RPR1 port shares the 2 x VC-4 bandwidth.
Protection	The RPR realizes protection for the EVPLAN service through two modes: Wrapping and Steering. Perform Wrapping for general protection switching at the beginning, and then perform Steering when the new topology and service path are established. Thus, no packet will be lost during protection switching and the switching time is shortened. The protection provided by the RPR allows the service free from SDH protection, thus saving the bandwidth used for protection. What is more, the bandwidth for protection can be used to transmit additional Ethernet services on RPR.

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