SONET Topologies and Upgrades

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1 CHAPTER 9 Note The terms "Unidirectional Path Switched Ring" and "UPSR" may appear in Cisco literature. These terms do not refer to using Cisco ONS 15xxx products in a unidirectional path switched ring configuration. Rather, these terms, as well as "Path Protected Mesh Network" and "PPMN," refer generally to Cisco's path protection feature, which may be used in any topological network configuration. Cisco does not recommend using its path protection feature in any particular topological network configuration. This chapter explains Cisco ONS CL and Cisco SONET topologies and upgrades. To provision topologies, refer to the Cisco ONS CL and Cisco Procedure Guide. Chapter topics include: 9.1 Path Protection Dual-Ring Interconnect for the, page Terminal Point-to-Point and Linear ADM Configurations, page Interoperability, page Path-Protected Mesh Networks, page Four Node Configurations, page OC-N Speed Upgrades, page Path Protection Dual-Ring Interconnect for the ONS MA The path protection dual-ring interconnect topology (path protection DRI) provides an extra level of path protection between interconnected path protection configurations. In DRIs, traffic is dropped and continued at the interconnecting nodes to eliminate single points of failure. Two DRI topologies can be implemented on the Cisco : the traditional DRI uses four Cisco s at the interconnect nodes, and the integrated DRI uses two nodes. To route circuits on the DRI, you must choose the DRI option during circuit provisioning. Circuits with the DRI option enabled will be routed on the DRI path. Cisco ONS CL and Cisco Reference Manual, R

2 9.2 Terminal Point-to-Point and Linear ADM Configurations Chapter 9 A hold-off timer sets the amount of time before a selector switch occurs. It reduces the likelihood of multiple switches, such as a service selector and a path selector. For example, if a path protection DRI service selector switch does not restore traffic, then the path selector switches after the hold-off time. The path protection DRI hold-off timer default is 100 ms. You can change this setting in the Path Protection Selectors tab of the Edit Circuits window. 9.2 Terminal Point-to-Point and Linear ADM Configurations You can configure ONS CLs and Cisco s in a terminal point-to-point network (two nodes) or as a line of add/drop multiplexers (ADMs) (3 or more nodes) by configuring the OC-N ports as the working path and a second set as the protect path. Unlike rings, terminal and linear ADMs require that the OC-N port at each node be in 1+1 protection to ensure that a break to the working line is automatically routed to the protect line. Note In a linear ADM configuration, two OC-N ports in 1+1 protection are connected to two OC-N ports in 1+1 protection on a second node. On the second node, two more OC-N ports are connected to a third node. The third node can be connected to a fourth node, and so on, depending on the number of nodes in the linear ADM. The ONS CL has only two optical ports. This restricts an ONS CL to being the end node in a linear ADM network since both ports are necessary to create the 1+1 protection group to the neighbor node. The MA has four optical ports, so it can operate either as a terminal or intermediate node in a linear ADM network. Figure 9-1 shows two ONS CLs in a linear ADM configuration with an. In this example, working traffic flows from the ONS Node 1/Slot 2/Port 2-1 to the Node 2/Slot 5, and from Node 2/Slot 12 to the ONS Node 3/Slot 2/Port 2-1. You create the protect path by placing Slot 2/Port 2-1 in 1+1 protection with Slot 2/Port 1-1 at Nodes 1 through 3. Figure 9-1 ONS CL Linear ADM Configuration ONS CL Slot 2 Port 2-1 to Slot 5 Slot 12 to Slot 2 Port 2-1 ONS CL Slot 2 Port 1-1 to Slot 13 to Node 1 Slot 6 Node 2 Slot 2 Port 1-1 Node 3 Protect Path Working Path Figure 9-2 shows three s in a linear ADM configuration. In this example, working traffic flows from Node 1/Slot 3/Port 2-1 to Node 2/Slot 4/Port 2-1, and from Node 2/Slot 3/Port 2-1 to the Node 3/Slot 4/Port 2-1. You create the protect path by placing Slot 3/Port 2-1 in 1+1 protection with Slot 4/Port 2-2 at Nodes 1 through Cisco ONS CL and Cisco Reference Manual, R7.0

3 Chapter Interoperability Figure 9-2 Linear ADM Configuration Slot 3 Port 2-1 to Slot 4 Port 2-1 Slot 3 Port 2-1 to Slot 4 Port 2-1 Slot 3 Port 2-2 to Slot 3 Port 2-2 to Node 1 Slot 4 Port 2-2 Node 2 Slot 4 Port 2-2 Node 3 Working Path Protect Path Interoperability The ONS CL supports up to two SONET SDCCs and one path protection per node. The supports up to four SONET SDCCs and two path protection per node. You can install ONS CL and nodes into a network comprised entirely of ONS CL or MA nodes or into a network that has a mix of ONS CL,,, and ONS nodes. The ONS CL and nodes interoperate with the and ONS nodes in linear or path protection configurations. Because connection procedures for these types of nodes are the same (for example, adding or dropping nodes from a path protection or linear configuration, or creating DCCs), follow the instructions in the Add and Remove Nodes chapter of the Cisco ONS CL and Cisco Procedure Guide whenever you make connections between ONS CL,,, and ONS nodes Subtending Rings Subtending rings reduce the number of nodes and cards required and reduce external shelf-to-shelf cabling. Figure 9-3 shows an with two subtending rings using ONS CL nodes. Figure 9-3 with Two ONS CL Nodes Subtending Path Protections ONS ONS Figure 9-4 shows an with two subtending rings path protection configurations. Cisco ONS CL and Cisco Reference Manual, R

4 9.3.1 Subtending Rings Chapter 9 Figure 9-4 with Two Subtending Path Protection Configurations Figure 9-5 shows a ring of ONS CL nodes subtended from a ring of nodes Figure 9-5 ONS CL Ring Subtended from an Ring ONS CL OC-3 or OC-12 BLSR OC-3 or OC-12 ONS CL Figure 9-6 shows a ring of nodes subtended from a ring of nodes. 9-4 Cisco ONS CL and Cisco Reference Manual, R7.0

5 Chapter Linear Connections Figure 9-6 Ring Subtended from an Ring BLSR OC-3, OC-12, or OC-48 OC-3, OC-12, or OC Linear Connections Figure 9-7 shows a basic linear or path protection connection between ONS CL and nodes. Note Please note that Figure 9-7 shows an ONS CL node, however; the illustration can be applied to both the ONS CL and nodes. Figure 9-7 Linear or Path Protection Connection Between and ONS or Nodes 1+1 Linear (Point-to-Point) ONS Cisco ONS CL and Cisco Reference Manual, R

6 9.4 Path-Protected Mesh Networks Chapter Path-Protected Mesh Networks In addition to single path protection configurations, terminal point-to-point or linear ADMs, you can extend ONS CL and traffic protection by creating path-protected mesh networks (PPMNs). PPMNs include multiple ONS CL and SONET topologies and extend the protection provided by a single path protection to the meshed architecture of several interconnecting rings. In a PPMN, circuits travel diverse paths through a network of single or multiple meshed rings. When you create circuits, CTC can automatically route circuits across the PPMN or you can manually route them. You can also choose levels of circuit protection. For example, if you choose full protection, CTC creates an alternate route for the circuit in addition to the main route. The second route follows a unique path through the network between the source and destination and sets up a second set of cross-connections. For example, in Figure 9-8, a circuit is created from the shown at Node 3 to the shown at Node 9. CTC determines that the shortest route between the two nodes passes through Node 8 and Node 7, shown by the dotted line, and automatically creates cross-connections at Nodes 3, 8, 7, and 9 to provide the primary circuit path. If full protection is selected, CTC creates a second unique route between Nodes 3 and 9 which, in this example, passes through Nodes 2, 1, and 11. Cross-connections are automatically created at Nodes 3, 2, 1, 11, and 9, shown by the dashed line. If a failure occurs on the primary path, traffic switches to the second circuit path. In this example, Node 9 switches from the traffic coming in from Node 7 to the traffic coming in from Node 11 and service resumes. The switch occurs within 50 ms. Figure 9-8 Path-Protected Mesh Network for ONS CL Nodes Source Node Node 2 Node 3 Node 5 Node 4 Node 1 Node 10 Node 8 Node 6 Node 7 Node 11 Protect traffic Node 9 Working traffic Destination Node = Primary path = Secondary path Cisco ONS CL and Cisco Reference Manual, R7.0

7 Chapter Path-Protected Mesh Networks For example, in Figure 9-9, a circuit is created from Node 3 to Node 9. CTC determines that the shortest route between the two nodes passes through Node 8 and Node 7, shown by the dotted line, and automatically creates cross-connections at Nodes 3, 8, 7, and 9 to provide the primary circuit path. If full protection is selected, CTC creates a second unique route between Nodes 3 and 9 which, in this example, passes through Nodes 2, 1, and 11. Cross-connections are automatically created at Nodes 3, 2, 1, 11, and 9, shown by the dashed line. If a failure occurs on the primary path, traffic switches to the second circuit path. In this example, Node 9 switches from the traffic coming in from Node 7 to the traffic coming in from Node 11 and service resumes. The switch occurs within 50 ms. Figure 9-9 Path-Protected Mesh Network for Nodes Source Node Node 2 Node 3 Node 5 Node 4 Node 1 Node 10 Node 8 Node 6 Node 7 Node 11 Protect traffic Node 9 Working traffic Destination Node = Primary path = Secondary path PPMN also allows spans with different SONET speeds to be mixed together in virtual rings. Figure 9-10 shows an with Nodes 1, 2, 3, and 4 in a standard OC-48 ring. Nodes 5, 6, 7, and 8 link to the backbone ring through the OC-12 fiber. The virtual ring formed by Nodes 5, 6, 7, and 8 use both the OC-48 and OC-12 cards. Cisco ONS CL and Cisco Reference Manual, R

8 9.5 Four Node Configurations Chapter 9 Figure 9-10 Virtual Ring for s Node 5 ONS 1510-MA Node 1 Node 4 Node 8 OC-12 OC-48 OC Node 6 Node 2 Node 3 Node Four Node Configurations You can link multiple ONS CL or nodes using their OC-N ports (also known as creating a fiber-optic bus) to accommodate more access traffic than a single ONS CL or can support. For example, to drop more than 21 DS-1s or 3 DS-3s (the maximum that can be aggregated in a single ONS CL node), you can link the nodes but not merge multiple nodes into a single ONS CL. You can link nodes with OC-N fiber spans as you would link any other two network nodes. The nodes can be grouped in one facility to aggregate more local traffic. 9.6 OC-N Speed Upgrades A span is the optical fiber connection between two ONS CL or nodes. In a span (optical speed) upgrade, the transmission rate of a span is upgraded from an OC-3 to OC-12 signal (ONS CL or ), from an OC-12 to OC-48 signal ( only), or from an OC-3 to OC-48 signal ( only), but all other span configuration attributes remain unchanged. With multiple nodes, a span upgrade is a coordinated series of upgrades on all nodes in the ring or protection group. The ONS CL nodes support the span upgrade wizard if you are upgrading two ONS CLs with 1+1 protection from OC-3 to OC-12. The nodes support the span upgrade wizard if you are upgrading two s with 1+1 protection from OC-3 to OC-12, OC-12 to OC-48, or OC-3 to OC-48. To perform a span upgrade, the higher-rate pluggable port module (PPM) must replace the lower-rate PPM in the same slot. If you are using a multi-rate PPM, you do not need to physically replace the PPM. All spans in the network must be upgraded. The 1+1 protection configuration of the original lower-rate PPM is retained for the higher-rate PPM. 9-8 Cisco ONS CL and Cisco Reference Manual, R7.0

9 Chapter Span Upgrade Wizard When performing span upgrades, Cisco recommends that you upgrade all spans in a network consecutively and in the same maintenance window. Until all spans are upgraded, mismatched PPM types will be present. If you are upgrading two ONS CL nodes with 1+1 protection from OC-3 to OC-12, or two nodes with 1+1 protection from OC-3 to OC-12, OC-12 to OC-48, or OC-3 to OC-48, Cisco recommends using the Span Upgrade Wizard to perform span upgrades. Although you can also use the manual span upgrade procedures, the manual procedures are mainly provided as error recovery for the wizard. The Span Upgrade Wizard and the manual span upgrade procedures require at least two technicians (one at each end of the span) who can communicate with each other during the upgrade. Upgrading a span is non-service affecting and will cause no more than three switches, each of which is less than 50 ms in duration. To initiate the span upgrade, right-click the span and choose Span Upgrade. Note Span upgrades do not upgrade SONET topologies (for example, a 1+1 group to a path protection). Refer to the Convert Network Configurations chapter of the Cisco ONS CL and Cisco Procedure Guide for topology upgrade procedures Span Upgrade Wizard The Span Upgrade Wizard automates all steps in the manual 1+1 span upgrade procedure, if you are upgrading two ONS CL or nodes. The wizard can upgrade both lines of a 1+1 group. The Span Upgrade Wizard requires that spans have DCCs enabled. The Span Upgrade Wizard provides no way to back out of an upgrade. In the case of an error, you must exit the wizard and initiate the manual procedure to either continue with the upgrade or back out of it. To continue with the manual procedure, examine the standing conditions and alarms to identify the stage in which the wizard failure occurred Manual Span Upgrades Manual span upgrades are mainly provided as error recovery for the Span Upgrade Wizard, but they can be used to perform span upgrades. You can perform a manual span upgrade on a 1+1 protection group, if you are upgrading two ONS CL or nodes. Downgrading can be performed to back out of a span upgrade. The procedure for downgrading is the same as upgrading except that you provision a lower-rate PPM (OC-3 for the ONS CL, or OC-3 or OC12 for the MA) and install a lower-rate PPM (if you are not using a multi-rate PPM). You cannot downgrade if circuits exist on the STSs that will be removed (the higher STSs). Cisco ONS CL and Cisco Reference Manual, R

10 9.6.2 Manual Span Upgrades Chapter Cisco ONS CL and Cisco Reference Manual, R7.0