RPR Technology and MNG PAN PDF

JTO Phase-II DNIT RPR Technology and MNG PAN 4 RPR TECHNOLOGY AND MNG PAN 4.1 LEARNING OBJECTIVES After reading this unit, you should be able to understand: RPR Technology Concept of MNG-PAN and OCPAN. Features...

JTO Phase-II DNIT RPR Technology and MNG PAN 4 RPR TECHNOLOGY AND MNG PAN 4.1 LEARNING OBJECTIVES After reading this unit, you should be able to understand: RPR Technology Concept of MNG-PAN and OCPAN. Features of MNG-PAN 4.2 INTRODUCTION TO RESILIENT PACKET RING (RPR) Resilient packet ring (RPR) is the technology for optimized and efficient packet networking over a fiber ring topology. This technology incorporates the various features of SDH technology like performance monitoring, protection mechanism and flexible deployment capabilities. RPR networks have the capability to carry jitter- and latency- sensitive traffic such as voice and video, in addition to Ethernet and Internet protocol (IP) services. Due to this Service providers are able to deliver multiple services on RPR solutions, instead of having data, voice, and video delivered over separate parallel networks. In this unique way RPR combines the best features of legacy Synchronous digital hierarchy (SDH) and Ethernet into one layer and thus maximize the profitability of the network operators. RPR networks are optimized to transport data traffic rather than circuit-based traffic. The unique feature of this technology is that it consumes bandwidth only between source and destination nodes and is more efficient than a time division multiplexing (TDM) technologies like SDH and also is able to deliver data efficiently with the resiliency and performance required by the latest applications in the networks. 4.3 THE KEY FEATURES OF RESILIENT PACKET RING TECHNOLOGY Table 1. Key Features Resilience Proactive span protection automatically avoids failed spans within 50 ms. Services Support for latency / jitter sensitive traffic such as voice and video. Also supports committed information rate (CIR) services. Spatial reuse: Unlike SDH, bandwidth is consumed only between Efficiency the source and destination nodes. Packets are removed at their destination, leaving this bandwidth available to downstream nodes on the ring. Scalable Supports topologies of more than 100 nodes per ring. Carries the Automatic topology discovery mechanism. JTO Phase-II Version 3.0 June 2021 Page 37 of 103 For Restricted Circulation JTO Phase-II DNIT RPR Technology and MNG PAN 4.4 RPR OPERATION RPR technology uses a dual counter rotating fiber ring topology. Both rings (inner and outer) are used to transport working traffic between nodes. By utilizing both fibers, instead of keeping one spare fiber for protection, RPR utilizes the total available ring bandwidth. These fibers or ringlets (as they are also called) are also used to carry control messages for topology updates, protection, and bandwidth control. All the time control messages flow in the opposite direction of the traffic that they represent. For instance, inner-ring traffic-control information is carried on the outer ring to upstream nodes. Figure 22: RPR Terminology By using bandwidth-control messages, a RPR node can dynamically negotiate for bandwidth with the other nodes on the ring. RPR has the capability to differentiate between low and high-priority traffic and can transmit high-priority packets before those of low priority. In addition, RPR nodes also have a transit path, through which packets destined to downstream nodes on the ring flow. Since RPR nodes have a transit buffer that is capable of holding multiple packets, it can transmit higher-priority packets while temporarily holding other lower-priority packets in the transit buffer. A. RESOURCE ALLOCATION AND CONTROL: There is no master node on the ring; bandwidth management and congestion control are fully distributed over all nodes, which implement control algorithms collectively. This is potentially a nice feature, as it combines the nodes‘ abilities for topology discovery with ease of adding or removing nodes from the ring. Each node processes three traffic streams: exit traffic destined for the node; ingress traffic entering the node locally and to be placed on the ring; and transit traffic destined for nodes further downstream. The basic issues are to ensure that ingress and transit JTO Phase-II Version 3.0 June 2021 Page 38 of 103 For Restricted Circulation JTO Phase-II DNIT RPR Technology and MNG PAN traffic don‘t interfere with each other‘s QOS and to share the ring resources fairly and avoid congestion. B. RECEIVE DECISION: Every station has a 48-bit MAC address. The Node will only receive the packets which have a matching MAC destination address. The MAC can receive both uni-cast and multi-cast packets. Multicast packets are copied to the host and allowed to continue through the transit path while the uni-cast packets are stripped from the ring and do not consume bandwidth on downstream spans. The rings are also carrying control packets that may be meant for the neighbouring node; these packets do not need a destination or source address. C. TRANSIT PATH Nodes with a non-matching destination address are allowed to continue circulating around the ring. Unlike point-to-point protocols such as Ethernet, RPR packets undergo minimal processing per hop on a ring. RPR packets are only inspected for a matching address and header errors. D. TRANSMIT AND BANDWIDTH CONTROL The RPR MAC can transmit both high and low-priority packets. The bandwidth algorithm controls is applied only for the bandwidth allotment of low-priority packets. High-priority packets are not subject to the bandwidth-control algorithm. The bandwidth- control algorithm ensures that nodes will not be disadvantaged due to its location on the ring or due to the changing traffic patterns. It only manages congestion, enabling nodes to maximize the use of any spare capacity. E. TOPOLOGY DISCOVERY RPR has a topology discovery mechanism that allows nodes on the ring to be inserted / removed without manual management intervention. After a node is inserted on the ring, it will circulate a topology discovery message to learn the MAC addresses of the other stations. Nodes also keep on sending these messages periodically (1 to 10 seconds). Each node that receives a topology message appends its MAC address and passes it to its neighbor. Eventually, the packet returns to its source with a topology map of the ring and the same is updated on the Node. The topology map will be used to determine which direction on the ring will provide the best path to the destination. F. PROTECTION: RPR has the ability to protect the network from single span (node or fiber) failures. When a failure occurs, protection messages are quickly dispatched. RPR has two protection mechanisms: JTO Phase-II Version 3.0 June 2021 Page 39 of 103 For Restricted Circulation JTO Phase-II DNIT RPR Technology and MNG PAN WRAPPING Nodes that are adjacent to the failed span will move the packets away from the failure by wrapping traffic around to the other fiber (ringlet). This mechanism requires that only two nodes participate in the protection event, other nodes keep on sending the traffic as normal. Figure 23: STEERING This protection mechanism notifies all nodes on the ring of the failed span. After receiving this notification, every node on the ring will adjust their topology maps to avoid this span Regardless of the protection mechanism used, the ring will be protected within 50 ms. 4.5 RPR BENEFITS EFFICIENCY It is efficient MULTICAST One RPR multicast packet can be transmitted around the ring and can be received by multiple nodes. Mesh topologies require multicast packets to be replicated over all possible path switching bandwidth. SPATIAL REUSE RPR uni-cast packets are stripped at their destination. Unlike SDH networks, where circuits consume bandwidth around the whole ring, RPR allows Bandwidth to be used on multiple idle spans. RESILIENCY Topology Discovery– Nodes are automatically added and removed from the topology map. JTO Phase-II Version 3.0 June 2021 Page 40 of 103 For Restricted Circulation  JTO Phase-II DNIT RPR Technology and MNG PAN Protection– RPR protects failed spans within 50ms. PERFORMANCE High-Priority Service– High-priority packets are delivered with minimal jitter and latency. SCALABILITY System throughputs range from 80 to 320 Gbps, typically scaling in 1-Mbit/s increments to 1 Gbit/s. Normally, RPR rings can support about 100 nodes. 4.6 MNG-PAN AND OC-PAN It is MPLS Based Next Generation Packet Aggregation Network which incorporates the MPLS-TP (MPLS-Transport Profile) technology for Transport network of telecom services. MNG PAN is an advanced Packet Aggregation Network solution designed for efficient multi-service aggregate of voice, video and data traffic from various access technologies including MSAN, DSLAM, FTTx, Broadband Wireless Access, as well as 3/4G mobile network base stations. The products offer high- performance aggregation and a broad feature set, including network-wide time/clock synchronization, carrier class sub 50ms recovery resiliency, guaranteed QoS and SLA enforcement, end-to-end multi-layer OAM. The MNG-PAN or OC-PAN switches shall collect the customer traffic like voice, video and data being generated through different access Broadband networks such as DSL, FTTH, MSAN, 3G Node B, Wi-Max etc and hand over to IP-MPLS core network. The MNG-PAN switches shall be centrally managed from the EMS deployed at NOC/DR-NoC. The MNG-PAN switches shall transparently handle IPV6 traffic. The MNG-PAN switches shall have 99.999% reliability. Figure 24: MNG-PAN is used for the aggregation of the traffic from various network elements being deployed in the BSNL Network JTO Phase-II Version 3.0 June 2021 Page 41 of 103 For Restricted Circulation  JTO Phase-II DNIT RPR Technology and MNG PAN 4.7 AGGREGATION NETWORK DEPLOYED IN MPLS BASED NETWORK PRIOR TO PAN SWITCHES It consists of multi-gigabit, Multi-Protocol Label Switching (MPLS) based IP Network in the form of a 2-layered centrally managed IP backbone network designed to provide convergent network supporting data, voice and video applications. The network is envisaged to support the QoS features with four different classes of traffic viz Platinum, Gold, Silver and Bronze along with MPLS- Traffic Engineering, Fast Reroute, multi-casting. This network consists of Core routers (A1, A2, A3 & A4) from different vendors in different locations. BSNL has deployed a RPR technology based Aggregation Network in the 98 cities for aggregating the Metro IP Traffic. There are around 1200 RPR based switches deployed as Metro Aggregation. BSNL has also deployed a LAN Switch Based Aggregation Network for aggregating the traffic from the other small cities (OCLAN switches) other than classified RPR based aggregation is deployed. There are around 3000 LAN switches deployed in the Network for OC City Aggregation (OCLAN) Typical deployment architecture is given below. Figure 25: Broadband Aggregation Network Architecture Prior to PAN Switches JTO Phase-II Version 3.0 June 2021 Page 42 of 103 For Restricted Circulation JTO Phase-II DNIT RPR Technology and MNG PAN 4.8 DEPLOYMENT ARCHITECTURE OF MNG-PAN AND OC- PAN BSNL deployed MNG-PAN Aggregation Network in the 15 cities 421 PAN-COAU & PAN 287 OC PAN The deployment of the MNG-PAN switch in the network shall be as below: Figure 26: Deployment Architecture of MNG-PAN and OC-PAN *PAN – COAU: Packet Aggregation Network – Central Office Aggregation Unit switch: for connecting to BNG or to MPLS routers *OC-PAN – Other City Packet Aggregation Network switch The OC-PAN ring will aggregate the traffic from all nodes and hand over the traffic to the upper MNG-PAN ring. The Central Office Aggregation Unit (COAU) switch of the PAN ring will aggregate the traffic from all the PAN nodes and hand over the traffic to the IP- MPLS core. The network shall support internetworking between the MPLS-TP and IP/MPLS domains by any of the solutions MPLS-TP Termination - service termination at the edge of each domain and traffic hand over UNI. MPLS-TP is a carried over IP-MPLS: service /Tunnel not terminated at the hand- off point, hand-off to core over S-VLAN tunnels or using GRE tunnels The equipment shall support the bridging functionality between MPLS-TP and IPMPLS domains. JTO Phase-II Version 3.0 June 2021 Page 43 of 103 For Restricted Circulation JTO Phase-II DNIT RPR Technology and MNG PAN 4.9 FEATURES OF MNG-PAN NETWORK 1. The solution is based on Pseudo Wire over MPLS-TP technology that supports an efficient Ethernet aggregation. 2. The PAN platform offers wide range of protocols, standards and interfaces coupled with highest reliability 3. Carrier-class set of features, including the carrier class sub 50ms recovery resiliency, 4. Hard QoS/SLA guarantees, 5. End to end and multi-layer OAM, network-wide time/clock synchronization, 6. Efficient multicast data distribution. 7. Range of interfaces up to 10GE 8. Low power consumption 9. Centralized management 4.10 ADVANTAGES OF MNG-PAN TRANSPORT NETWORK 1. Scalability: Support of electrical and optical Ethernet interfaces from FE to 10GE. Large switching capacity. 2. Reliability: Carrier class reliability with fully redundant hardware architecture. 3. Resilience: Various protection schemes, sub-50ms failure recovery. 4. Manageability: Enhanced OAM capability with end-to-end service management. NMS-based operation. 5. Inter-operability: Compliant with ITU-T MPLS-TP standard. Easy integration with core IP/MPLS or OTN networks. 6. Bandwidth Efficiency: Packet nature of the network with flexible data-pipes enables users to request the service in smaller increments and provides better utilization at the aggregation level. 7. Lower TCO: Low power consumption; bandwidth efficiency due to optimized packet aggregation; fast fault isolation and simple management; smaller form factor. 4.11 CONCLUSION Today when service providers are trying to build scalable, feature-rich networks that can deliver profitable value-added services like multi protocol label switching JTO Phase-II Version 3.0 June 2021 Page 44 of 103 For Restricted Circulation JTO Phase-II DNIT RPR Technology and MNG PAN (MPLS) virtual private networks (VPNs); carrying voice, video, and data services, RPR can be one solution which can meet these requirements effectively and also at the same time will provide with carrier class reliability and scalability. So the RPR is seen by the operators as the required bridge technology which can fulfill networks‘ much needed requirement of transition from circuit to packet base services. The MNG-PAN and OC-PAN switches shall collect the customer traffic like voice, video and data being generated through different access Broadband networks such as DSL, FTTH, MSAN, 3G Node B, Wi-Max etc and hand over to IP-MPLS core network. JTO Phase-II Version 3.0 June 2021 Page 45 of 103 For Restricted Circulation