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Campus LAN Design

Campus LAN Design. NW97_EMEA_301. 1. Introduction. Different user requirements dictate different network solutions How to decide what model of network to build? For each of the models: Define network requirements Analyze the network design architecture Review required Technologies.

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Campus LAN Design

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  1. Campus LANDesign NW97_EMEA_301 1

  2. Introduction • Different user requirements dictate different network solutions • How to decide what model of network to build? • For each of the models: • Define network requirements • Analyze the network design architecture • Review required Technologies

  3. Agenda • Building Blocks • Campus Architectures • Campus Design

  4. Building Blocks

  5. Backbone only in Campus (rarely Desktops) • Interoperable Redundancy & Loadsharing by PNNI1 • VLAN Standard (LANE) • Full QOS (PBX Connection) • Scaling Issues in large Campus • Moderate Cost 155 Mbps 622 Mbps FDX ATM • End to End Technology • limited QOS (COS) • Multimedia over IP • FDX = NO Collisions ! • Existing Knowhow • Very Low Cost 10 Mbps 100 Mbps 1000 Mbps FDX “802.3” Ethernet LAN Backbone Technologies “classical” L1 Install & Forget Robust & Redundant if Concentrators used ! Very Fast Failover todays L2, L3 FDX Topo like Ethernet Expensive... FDDI

  6. 155 or 622 Mb/s Central Switch ATM Physical Topology Building Backbone Campus Backbone 10/100 Mb/s Ethernet 4/16 TR 25/155 Mb/s ATM 155 or 622 Mb/s WAN ATM

  7. Ethernet Physical Topology Building Backbone Campus Backbone 10/100 Mb/s 4/16 TR(Future) up to 2 Gb/s 10/100/1000 Mb/s up to 8 Gb/s WAN ATM ATM

  8. 9u Singlemode Gigabit Ethernet Distances Long Reach Lasers: 15 to 60 km { 1000BaseLX ~1300 nm 50u Multimode 62.5u Multimode { 50u Multimode 1000BaseSX ~850 nm 62.5u Multimode { “Long-Haul Copper” (802.3ab) 4 pr Cat 5 UTP { Balanced Shielded Cable 1000BaseCX Copper C // 100m 260m 550m 440m 25m 3 km Wiring Closet Mach. Room Building Backbones Campus Backbone

  9. Multi VLAN Server VLAN 1 L2 Wire Speed VLAN 4 L3 less performant Common Server VLAN 2 80+% Local Traffic Current Campus Design • Smaller L2 Domains: • Faster convergence, better resilience • Less broadcast traffic • Security domains

  10. New Trafficpatterns • WEB Technology &Distributed Systemsarrived • Desktop-to-Desktop Video Interactive Applications Intranets

  11. Small localized Access VLANs 95% Non Local Traffic Single VLAN Backbone VLAN 2 Central Server VLANs Existing Structure Emerging Campus Structure • Multilayer Switches provide L2/L3 Features • Control by Access lists • Selective BC forwarding • Advanced Services L2 =L3 Performance

  12. NetFlow™ Switching Multilayer Switch Backbone Inter VLAN Switching Tag Switching Router Backbones Scalable Internet/Intranet Multilayer Switching Solutions Multilayer Switching Fusing Routing and Switching Multi Protocol Over ATM Inter ELAN Cut-through Switching (MPOA)—ATMF Standard

  13. Cut Through Path Remainder of Flow Multiprotocol over ATM ATMF Standard Based on LANE & NHRP Limited Security No IP MC Support in Standard A ELAN A ATM Backbone ELAN B MPOA Server Handles Initial Flow B MPOA Client

  14. NetFlow Switching • NetFlow switching • High performance Layer 3 switching • Fully compliant with all IETF standards • No Host changes required • Flow management • Planning, administration and troubleshooting • NetFlow services • Security services • Class of serviceenablement

  15. VLAN Y VLAN X NFLS First Packet of a Flow Full Router or RSM Route Processor Tasks Catalyst Switch with NFFC • Forwarding: • Route Table • Security: • Access list • Management: • Accounting Application Campus Client Server Net Flow Lan Switching

  16. VLAN Y VLAN X NFLS Remainder of Flow Full Router or RSM Catalyst NFFC • Learn Flow • Build Cache: • Source Address, • Dest. Address, • Application • Forward Packets • InterVLAN • Gather Statistics Catalyst Switch with NFFC L3 cut-through switching ASIC in Catalyst (Services are maintained) Campus Client Server

  17. Flow Consolidation NetworkPlanning Accounting/Billing Si Flow Profiling Si Network Monitoring Traffic Director Flow Consumers Integrated NetFlow Management Routers Switches RMON Probe Flow Switching and Data Export Flow Collection

  18. Campus Architectures

  19. Four Basic Campus Architectures CampuswideVLANs HierarchicalL2/L3 Network Campuswide VLAN with Ethernet Backbone Layer 2/Layer 3 with Ethernet Backbone Frame-Switched Backbone ATM-Switched Backbone Campuswide VLAN with ATM Backbone Layer 2/Layer 3 with ATM Backbone

  20. Campuswide Vlans CampuswideVLANs HierarchicalL2/L3 Network Campuswide VLAN with Ethernet Backbone Layer 2/Layer 3 with Ethernet Backbone Frame-Switched Backbone ATM-Switched Backbone Campuswide VLAN with ATM Backbone Layer 2/Layer 3 with ATM Backbone

  21. Campuswide VLANs • Users are Members of a specific VLAN (Subnet)independent of physical moves • Each VLAN could have a common set of security requirements for all members • Today most traffic is local to VLANWith wirespeed L3 Performance no longer required

  22. I.e. User VLAN Membership via MAC address with VMPS Feature on moves Layer 3-4+ Routing and Filtering Access Control, Accounting Central ACLNetflow RMON Campuswide VLANs Issue: Scalability of campuswide L2 VLANs

  23. VLAN ID SRC MAC Address Campuswide VLANs I.e. User VLAN Membership via MAC address with VMPS Feature on moves Layer 3-4+ Routing and Filtering Access Control, Accounting Central ACLNetflow RMON Virtual Membership Policy Server

  24. Campuswide Vlans =>Ethernet CampuswideVLANs HierarchicalL2/L3 Network Campuswide VLAN with Ethernet Backbone Layer 2/Layer 3 with Ethernet Backbone Frame-Switched Backbone ATM-Switched Backbone Campuswide VLAN with ATM Backbone Layer 2/Layer 3 with ATM Backbone

  25. Workgroup Servers Campuswide VLAN =>Ethernet Backbone Switched Ethernet • Majority of local Traffic • Static IP addressing is common (DHCP can be used, too) • Common security requirements per VLAN • Lots of adds, moves and changes • All VLANs across all switches and the backbone over time • Spanning Tree Loadin Distribution/CoreLayer !! Wiring Closet ISL Tagging DistributionLayer ISL Tagging Core Layer Fast/Gigabit Ethernet Inter-VLAN Routing Enterprise Servers

  26. Campuswide Vlans => ATM CampuswideVLANs HierarchicalL2/L3 Network Campuswide VLAN with Ethernet Backbone Layer 2/Layer 3 with Ethernet Backbone Frame-Switched Backbone ATM-Switched Backbone Campuswide VLAN with ATM Backbone Layer 2/Layer 3 with ATM Backbone

  27. Campuswide VLAN => ATM Backbone Switched Ethernet • Best for local Traffic • Lots of adds, moves, and changes • Static IP addressing common (DHCP can be used) • Common security requirements per ELAN • Traditional voice/video in ATM core • Multiple VLAN (ELAN) membership across all wiring closets • ATM VC CountScaleability !!! Wiring Closet ATM OC-3 MultipleELANs LANE Core Layer Workgroup Servers VC Count !! ATM with PNNI Inter-ELAN Routing Enterprise Servers

  28. LECS LES BUS Ethernet Clients & Server LAN Emulation - Scalability Issues Required SVC´s for 3 Clients... ATM attached LANE Clients need HIGH Performance ATM Hardware to handle large number of SVC´s LAN connected Clients CAN scale better(depends on Switch Implementation)

  29. Campuswide VLAN =>Ethernet Distribution, ATM Core Switched Ethernet • Best for local Traffic • Lots of adds, moves, and changes • Static IP addressing common (DHCP can be used) • Common security requirements per ELAN • Traditional voice/video in ATM core • Multiple VLAN (ELAN) membership across all wiring closets • Much lower ATM VC Requirements • SPT Load ! Wiring Closet ISL Tagging DistributionLayer SPT Load ! Workgroup Servers ATM Lane Core Layer Inter-ELAN Routing ATM PNNI Enterprise Servers

  30. Campuswide VLAN with ATM — Required Technologies • LAN Emulation • Inter-ELAN switching on routers • High call/sec setup rate on ATM switch • High BUS performance (mainly for multicast) • PNNI for auto-rerouting in ATM core • LANE Services Redundancy (SSRP) • HSRP with LANE • Sophisticated switch debugging tools

  31. Hierarchical Design CampuswideVLANs HierarchicalL2/L3 Network Campuswide VLAN with Ethernet Backbone Layer 2/Layer 3 with Ethernet Backbone Frame-Switched Backbone ATM-Switched Backbone Campuswide VLAN with ATM Backbone Layer 2/Layer 3 with ATM Backbone

  32. Hierarchical L2/L3 Network • Users are still grouped into VLANS (subnets)for overall network scalability • Layer 3 performance approaches Layer 2 performance • User’s VLAN membership changes as they move • Traffic patterns nonlocal or unknown

  33. L3 L3 L3 Hierarchical L2-L3 Campus DHCP Service User VLANs Terminate Here Block 1 Block n Introduce Multilayer Switches at the Distribution Fully Structured Scaleable L3 Core Server Block

  34. Hierarchical L2/L3 Network • Layer 2 and Layer 3 used to advantage • No penalty for L3 with NetFlow™ LAN switching • Matches the new nonlocal traffic pattern • VLANs for scalability and trunking • VLANS used as a design tool to optimize traffic flows • VLAN membership changes with moves • Preserves scalability, addressing, policy • Fast convergence at all layers of the network

  35. Hierarchical ATM CampuswideVLANs HierarchicalL2/L3 Network Campuswide VLAN with Ethernet Backbone Layer 2/Layer 3 with Ethernet Backbone Frame-Switched Backbone ATM-Switched Backbone Campuswide VLAN with ATM Backbone Layer 2/Layer 3 with ATM Backbone

  36. L2/L3 Network=> ATMF MPOA Switched Ethernet Wiring Closet • L3=L2 performance • NO L3/L4 Accesscontrol • Typical single Subnet per Closet • DHCP for IP mobility • User’s VLAN membership changes with moves • Most traffic leaves ELAN • Traditional Voice/Video in ATM core Multiprotocol Client (MPC) ATM OC-3 Core Layer MPOA ATM with PNNI Route Server (MPS) MPC Workgroup and Enterprise Servers

  37. L2/L3 Network =>Ethernet Distribution, ATM Core Switched Ethernet • L3=L2 performance • L3/4 NetFlow Services • Typical single Subnet per Closet • User’s VLAN membership changes with moves • DHCP for IP mobility • Most traffic leaves ELAN • Traditional Voice/Video in ATM core Wiring Closet ISL Tagging NetFlow L3/L4 DistributionLayer ATM Lane Core Layer ATM PNNI Enterprise Servers

  38. Hierarchical Ethernet CampuswideVLANs HierarchicalL2/L3 Network Campuswide VLAN with Ethernet Backbone Layer 2/Layer 3 with Ethernet Backbone Frame-Switched Backbone ATM-Switched Backbone Campuswide VLAN with ATM Backbone Layer 2/Layer 3 with ATM Backbone

  39. L2/L3 Network =>Ethernet Switched Ethernet • L3=L2 performance • L3/4 NetFlow Services • Typical single Subnet per Closet • User’s VLAN membership changes with moves • DHCP for IP mobility • ISL used to maximize uplink utilization Wiring Closet ISL Tagging NetFlow L3/L4 DistributionLayer ISL Tagging Core Layer FE, GE Enterprise Servers

  40. IP Mobility • DHCP used for those clients who move frequently • Client receives valid IP address, mask, gateway independent of location • Similar in principle to Novell client auto addressing • DHCP is the best solution for IP mobility • If DHCP is not possible=> Local Area Mobility can be considered

  41. Campus Design

  42. Switch Domain ISL Fast Ethernet . . . . Distribution Layer (NetFlow LAN Switching) Workgroup Servers Core Layer Enterprise Servers Overall L2/L3 Campus Architecture Switched Ethernet . . . . . . . . Wiring Closet

  43. Desktop Connectivity • Provision switched Ethernet to the desktop • Use 10/100 ports for Migration to Fast Ethernet • Catalyst™ 5500 for high density or chassis fault tolerance Switched Ethernet to the Desktop . . . . Wiring Closet

  44. . . . . etc. 50 51 50 51 2 3 2 3 4 5 4 5 6 7 6 7 VLAN Allocation • VLANs used to optimize network design • Use VLAN trunking to scale uplink bandwidth • Simple—maximize determinism of traffic flows • Subnet size is approximately the size of a wiring closet VLAN#

  45. Wiring Closet Interconnection Switch Domain . . . . . . . . • Redundant Fast Ethernet ISL trunks • Switch domain defined by building size • Deploy RSM/NetFlow LAN switching in distribution layer Wiring Closet Fast Ethernet/EtherChannel ISL . . . . Distribution Layer

  46. Wiring Closet Detail View 3 2 3 4 5 4 5 2 VLANs: Block 1 • Both uplinks are used for traffic • Each uplink backs the other up • Each Rootbridge backs the other up • VLAN trunking to optimize design … 2 3 3 2 2 3 3 3 4 5 5 4 4 5 5 4 X = forwarding Y = blocking Wiring Closet FE ISL FE ISL STP Root for Even VLANs STP Root for Odd VLANs Distribution Layer

  47. Redundancy Analysis 3 2 3 4 5 4 5 2 VLANs: Block 1 • Fail any link • Fail any distribution layer switch • Traffic automatically flows on alternate link • UplinkFast used to converge in seconds … 3 2 2 3 3 3 4 5 5 4 4 5 5 4 X = forwarding Y = blocking Wiring Closet X Distribution Layer

  48. UplinkFast Feature Listening Learning Blocking Forwarding UplinkFast States Traditional Listening Learning Blocking Forwarding

  49. SA “3” Multicast “Dummy” Packets with Source MAC Addresses MCast SA “2” MCast SA “1” MCast UplinkFast MAC Addresses “1” “2” “3” Wiring Closet Forwarding tables updated by Multicast “Dummy” Packets Distribution Layer

  50. 2 3 10 3 2 10 Scale the Bandwidth with VLANs 3 2 3 4 5 4 5 2 VLANs: Block 1 • Add another VLAN and Trunk between wiring closet and distribution layer • Readdressing is automatic with DHCP … 2 3 3 2 2 3 3 3 4 5 5 4 4 5 5 4 X = forwarding Y = blocking Wiring Closet Distribution Layer

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