Cisco Systems Network Router manual Planning Guidelines for Hierarchical Networks

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Chapter 2 Interoperability and Performance Planning

Planning Guidelines for Hierarchical Networks

•Although the number of network nodes in your network might not dictate a hierarchical topology, other network requirements can. For example, an anticipated network expansion might be easier later if you plan for it now.

•Consider future growth when planning peer groups. If the number of existing nodes is approaching the limit of a single peer group, consider using a hierarchical topology so that you do not have to reconfigure nodes later when the network size expands.

Planning Guidelines for Hierarchical Networks

When you have a plan for dividing your network into multiple peer groups, the next step is to plan communications between those peer groups. To enable communications between peer groups, you will need to identify a peer group leader for each peer group. The following sections provide planning guidelines for the peer group leaders and border nodes in a hierarchical network.

Planning Guidelines for Peer Group Leaders

Peer group leaders are the logical nodes that represent their peer group at the next higher level in the PNNI hierarchy. Peer group leaders are introduced in Chapter 1, “Introduction to PNNI.” When planning for peer group leaders, consider the following facts and guidelines:

•For a peer group to communicate with another peer group, the peer group must have at least one node that is capable of acting as peer group leader.

•It is good design practice to configure multiple nodes within a peer group to serve as peer group leader. The peer group priority is a configurable parameter that determines which of the peer group leader candidates becomes peer group leader.

•To compensate for the additional processing requirements of peer group leaders, consider reducing the traffic load for the peer group leader switch and avoid using the same switch as both a peer group leader and a border node.

Planning Guidelines for Border Nodes

Border nodes are physical nodes that are members of one peer group and have PNNI outside-links to member nodes of other peer groups. Border nodes are introduced in Chapter 1, “Introduction to PNNI.” To compensate for the additional processing requirements of border nodes, consider reducing the intra-peer-group traffic load for the border node and avoid using the same switch as both a border node and a peer group leader.

 

 

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

 

 

 

 

 

 

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

 

 

2-7

 

 

 

 

 

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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
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