Cisco CCIE Fundamentals Network Design

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.SAP Filters on WAN LinksSAP filters, which are currently available for serial, Token Ring, and Ethernet interfaces, can be usedto prevent local NetBIOS and other broadcasts from traversing the RSRB/SDLLC WAN.Toimplement SAP filter logic on the RSRB/SDLLC WAN interface, it is desirable to place the code atthe RSRB level independent from the encapsulation type on the interface.The same filter codeshould work for direct HDLC encapsulation, TCP/IP encapsulation, and FST encapsulation.Inaddition to filtering by SAP address, SAP filters can also be used to filter packets by NetBIOS name.The commands, which are available in Software Release 9.1.(9), are the same as those used for SRBon the Token Ring interface:" The access-list list global configuration command builds the access list." The rsrb remote-peer ring-group interface configuration command filters by Local ServiceAccess Point (LSAP) address or by NetBIOS station name on the RSRB WAN interface." The netbios access-list host global configuration command builds a NetBIOS access filter byhost name.SRB Design ChecklistBefore implementing a source-route bridging (SRB) network, be sure to familiarize yourself withthe technical reference material in the Router Products Configuration Guide and the Router ProductsCommand Reference publications that deals with SRB internetworking.4-46 Cisco CCIE Fundamentals: Network DesignSummaryNext, read the Multiport Bridging through WAN Framing sections earlier in this chapter.Depending on your implementation, you should review the IP Routing Protocol Selection for SRBNetworks and SRB Network Design sections earlier in this chapter.If you require more than eightrouters, continue as follows:Step 1 Evaluate the following requirements:" Determine which protocols are to be used.Relevant options are hierarchical SystemsNetwork Architecture (SNA) and NetBIOS.If you are running hierarchical SNA,determine the link speeds to the core front end processor (FEP) sites." Determine whether parallel paths exist in the network either between individualrouters or in the general network.If they do, refer to the WAN Parallelism sectionearlier in this chapter." Determine whether the network requires greater than 2-kilobyte frames to be sentacross WAN links.If so, refer to the WAN Frame Sizes section earlier in thischapter.Step 2 If the access ring and the FEP-connected sites exceed 15 token rings, you must addressthe following issues:" Determine whether local acknowledgment is a requirement.Refer to the LocalAcknowledgment Recommendations section earlier in this chapter." Select an encapsulation method.Refer to the WAN Framing section." Design a network topology incorporating the rules outlined in the SRB NetworkDesign section." Select a routing protocol described in the WAN Parallelism and IP RoutingProtocol Selection for SRB Networks sections.Step 3 If performance is important for your internetwork, review the IP Routing ProtocolSelection for SRB Networks section.Step 4 Prepare each router s configuration for the following:" SRB (Refer to the Explorer Packets and Propagation and WAN Framingsections.)" IP route tuning (Refer to the IP Routing Protocol Selection for SRB Networkssection.)Step 5 Turn on proxy explorer as needed.Refer to the Explorer Packets and Propagationsection.Step 6 If the network requires NetBIOS, proceed as follows:" Turn on NetBIOS name caching." Limit the explorer packet processing queue to 20 entries.Refer to the ExplorerPackets and Propagation section.Step 7 If you expect to exceed 250 Token Rings, contact your technical support representativefor additional information.SummaryThis chapter discussed source-route bridging (SRB) and remote source-route bridging (RSRB).Itaddressed the challenges of this environment and helped network designers successfully implementSRB within a large, multiprotocol topology, including covering the following areas:Designing SRB Internetworks 4-47Summary" SRB technology and implementation overview" Internet Protocol (IP) routing protocol selection and implementation" SRB network design recommendations and guidelines4-48 Cisco CCIE Fundamentals: Network DesignC H A P T E R 5Designing SDLC, SDLLC,and QLLC InternetworksThis chapter addresses some of the special requirements for implementing routing technology withinIBM System Network Architecture (SNA) environments.Internetworking within an SNAenvironment often involves making special accommodations for devices that were not originallydesigned for connection to meshed internetworks.This chapter describes three techniques designed to enable internetworking capabilities forSNA-based network architectures:" SDLC via STUN" SDLLC Implementation" QLLC ConversionThe sections that describe serial tunneling (STUN), Synchronous Data Link Control (SDLC) overthe Logical Link Control, type 2 (LLC) protocol (SDLLC), and Qualified Logical Link Control(QLLC) focus on the following topics:" Technology overview and issues" Router technology options, implementation guidelines, and configuration examplesNote For information about IBM serial lines, refer to Appendix B, IBM Serial LinkImplementation Notes.SDLC via STUNSDLC via serial tunneling (STUN) encapsulates SDLC frames into Internet Protocol (IP) packetsand routes the encapsulated packets over IP-supported network media.The SDLC frame istransmitted without modification, and the information within the frame is transparent to the network.All SNA physical unit (PU) types are supported.This section focuses on the SDLC data-linkprotocol and its various configurations and then explains how to implement STUN [ Pobierz całość w formacie PDF ]

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