Cisco Systems Network Router manual Ppeer

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Chapter 1 Introduction to PNNI

The Hierarchical PNNI Network Topology

Figure 1-3 Example Hierarchical PNNI Network Topology Showing a Two-Level Hierarchy

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group 2

Peer group 1

Peer

group 3

PNNI networks

Level 40

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group 5

Level 56

Peer group 4

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In a hierarchical PNNI network, logical levels are used to manage the portions of the PNNI database that describe communications paths between individual peer groups. PNNI divides the entire network database into manageable chunks, and the portions that describe communications between peer groups are managed by LGNs that operate at levels above the lowest-level peer groups.

Within each level 56 peer group in Figure 1-3, all the nodes exchange PTSEs to build and maintain a PNNI database that describes communication paths to all other nodes within the peer group. However, individual peer group nodes do not exchange PTSEs with nodes outside their peer group. Instead, LGNs are created during configuration to operate at level 40 and communicate with other level 40 nodes.

The level 40 nodes in Figure 1-3are all part of the same level 40 peer group and exchange PTSEs in the same way as do the lower level nodes. The level 40 LGN for each peer group in Figure 1-3is called a peer group leader and provides summarized information to its child peer group about the other peer groups represented at level 40. Each peer group leader also provides summarized peer group information about its child peer group to the other peer group leaders at the same level. Peer Group 1, for example, learns about 8 nodes: 4 physical nodes are in its own peer group, and 4 LGNs are actually representing other peer groups.

To demonstrate how hierarchical networks support more nodes than single peer group networks, consider the two-level example in Figure 1-3. A single peer group can support 160 nodes. In Figure 1-3, there are 5 peer groups, so each peer group will learn about 4 LGNs that will represent the other peer groups. This allows each peer group to support up to 156 physical nodes (160 - 4 = 156). The hierarchical network in Figure 1-3can support 780 physical nodes (156 * 5 = 780).

 

 

Cisco PNNI Network Planning Guide for MGX and SES Products, Release 5

 

 

 

 

 

 

Part Number OL-3847-01 Rev. D0, April, 2004

 

 

1-5

 

 

 

 

 

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Contents Text Part Number OL-3847-01 Rev. D0 Corporate HeadquartersCopyright 2003, Cisco Systems, Inc All rights reserved Iii N T E N T SCompatible Standards Worksheets Part Number OL-3847-01 Rev. D0, April Vii G U R E SViii B L E S Part Number OL-3847-01 Rev. D0, April Audience ObjectivesOrganization Xii ConventionsDocumentation Notes for the April 2004 Product Releases DocumentationRelated Documentation XiiiXiv Technical Manual Order of UseTerms Technical Manual Titles and DescriptionsXvi Xvii Xviii Xix Reference Guides Xxi Xxii Document Title DescriptionXxiii Xxiv Xxv Xxvi Cisco.com Obtaining DocumentationOrdering Documentation XxviiChapter Changes Changes to This DocumentXxviii Documentation Feedback Obtaining Technical AssistanceCisco TAC Website Opening a TAC CaseTAC Case Priority Definitions Obtaining Additional Publications and InformationXxx Xxxi Xxxii Pnni Network Database Introduction to PnniSingle Peer Group Topology Example Single Peer Group Topology Hierarchical Pnni Network TopologyPeer group Ppeer Simple Node Representation Peer Group LeadersSimple Node Representation Complex Node RepresentationBorder Nodes Pnni Internetworking with AiniHierarchical Pnni Network Benefits Example Pnni Internetworking with Aini Topology Pnni Internetworking with IispPart Number OL-3847-01 Rev. D0, April Compatible Standards SpecificationsCapabilities PXM45PXM1E PXM45/BSES Capabilities SESConnection Type Switch Connections CWM Endpoints Connection Limit AdjustmentsSVC DAX SpvcParallel Links Between Adjacent Switches Install Redundant Hardware in SwitchesPhysical Network Planning Multiple Links Between Adjacent Peer Groups Planning Guidelines for Individual Peer GroupsMultiple Links to an External Network Multiple Paths Between Network NodesPlanning Guidelines for Peer Group Leaders Planning Guidelines for Hierarchical NetworksPlanning Guidelines for Border Nodes Part Number OL-3847-01 Rev. D0, April Address Planning Overview Address and Closed User Group PlanningPnni Addressing Example Selecting an ATM Address Format Planning Address Configuration SettingsESI SEL IDP DSP Supported Address FormatsGuidelines for Selecting an Address Format ATM Field Description Default ValuesAddress Registration Authorities Selecting a Pnni LevelCategory Type Authorities DCC4shows an example topology of a Pnni MPG WAN Part Number OL-3847-01 Rev. D0, April Level Peer Group ID Portion of ATM Address Bytes LengthSelecting the Pnni Peer Group ID Default Peer Group ID20-byte Node Address Selecting the ATM AddressSelecting the Spvc Address Prefix Selecting the Ilmi Address PrefixPlanning Address Prefixes for Aini and Iisp Links Additional Guidelines for Creating an Address Plan Selecting Static Addresses for UNI PortsClosed User Group Example Closed User Group OverviewSelecting an Interlock Code Planning CUG Configuration SettingsSelecting an Index Selecting CPE Addresses Selecting Internal CUG Access OptionsSpecifying a Preferential CUG Selecting External CUG Access OptionsWorksheets Selecting a Default CUG AddressCUG Part Number OL-3847-01 Rev. D0, April How MGX and SES Nodes Select Routes Administrative WeightLink and Route Metrics Cell Delay Variation Cell Transfer DelayAvailable Cell Rate Maximum Cell Rate Shortest Path Table RoutingShortest Path Tables Service Class Acronym Definition Guidelines Class of Service TablesCTD CDV Traffic MetricHow SPVCs and SPVPs use the SPTs How SVCs and SVPs use the SPTsOn-Demand Routing How MGX and SES Nodes Select LinksLoad Balancing for SPT and On-Demand Routing Service Additional Routing Features in MGX and SES NodesPreferred Routing CLR0+12Grooming Priority RoutingPriority Bumping Soft ReroutingBlocking Pass-Through Connections Nodal Point-to-Multipoint Branch RestrictionAXSM/B AXSM/AAXSM-E AXSM-XGFarthest Node Branching Part Number OL-3847-01 Rev. D0, April Aesa ABRAini Ansi APSCBR P2MPCTD IN-2CWM CUGDIN IN-3IN-4 Pnni PGLMGX SES IN-5IN-6 UNI UBRTAC IN-7IN-8