1. Switched Campus Intranets
1134_04F8_c4

2. Network Design Engineer
Please see the white paper: Designing High Performance Campus Intranets with Multilayer Switching
Geoff Haviland
Network Design Engineer
May 1998

3. Designing Intranets with Multilayer Switching
Technology Considerations
Design Alternatives
The Multilayer Design

4. Technology Considerations
Issues with flat-bridged networks
Spanning tree limitations
Switching at L2, L3, and L4
L2 = L3 = L4 switching performance
Multilayer switch specialization
High-performance design requirements
Fast convergence
Deterministic paths
Deterministic failover
Scalable size and throughput
Server farms and the new 80/20 rule

5. The Key Aspects of L3 Switching (The Same Things Routers Do)
Packet
Switching
(NetFlow, Express Forwarding)
Packet-by-Packet Switching in Hardware, L2 = L3 = L4 Performance
Route
Processing
(OSPF, EIGRP, BGP4, PIM, RIP, etc)
Path Determination, Load Balancing, and Summarization, Keys to Scalability and Stability
Intelligent
Network
Services
(HSRP, Access Lists, Mobility, TACACS, Debug, QoS, NTP, etc)
Policy Enablers, Access Lists, Proxy Services, QoS Features, Debugging, Keys to Manageability, Troubleshooting, and Applications Availability

6. Campus Design with Switching
Spanning tree protocol
Hub and router design
Campus-wide VLANs
MPOA
Multilayer designs

7. Spanning Tree Considerations
Root election
Root priority, Root ID
Shortest path to the root
Path cost, port priority, Port ID
Convergence
Forward delay, MAX age, Hello time
Load balancing

8. Broadcast Domain (=Subnet =VLAN = ST)
Number of users?
Network protocols like IP, IPX®, NetBIOS, routing protocols, OSPF, SAP, EIGRP, RIP
Spanning tree considerations, load balancing, traffic flow
MTU sizes, frame translations, frame fragmentation, SRB/SRS integration
Broadcast domain is a failure domain!

9. Root Election B = Blocking F= Forwarding
BPDU = Bridge Protocol Data Unit
Root Priority = 2 bytes (32768)
Root ID = Root Priority + Bridge ID
Lower Priority, Lower ID
Port Cost = default (10^9/line-rate)
Port ID = Port Priority + Port ID
Blocked
Port B
Root
Port
Designated
Port F F F F
Root
Port
Designated
Bridge
Root Bridge
Root Bridge Priority 200

10. Spanning Tree New Port Cost Values
Root Election
Spanning Tree New Port Cost Values
Based on 802.1D Spec
Speed
10 Gbs
1 Gbs
622 Mbs
155 Mbs
100 Mbs
45 Mbs
16 Mbs
10 Mbs
4 Mbs
Cost 2 4 6 14 19 39
80/63
100
250

11. Convergence Tuning: Diameter
Port States = Blocking, Listening, Learning, Forwarding
BPDU Hello = 2 seconds (default)
Forward delay = 15 seconds (default)
Maximum Age = 20 seconds (default)
Convergence = 2 * forward-delay + Maximum Age
Root
Port F
Root
Port
Designated
Port X F F F
Root
Port
Designated
Bridge
Root Bridge
set spantree root 10
Tuning: Diameter

12. STP Port States Blocking Listening Learning Forwarding
No traffic through port, still receiving BPDUs
Listening
Learning
No traffic through port, and building bridge table
Forwarding
User traffic across port, and TX or RX BPDUs

13. Recovery Tuning Uplink Fast HSRP OSPF EIGRP STP
No tuning—3 seconds—wiring closet only
Only applies to VLANS with loop (triangle)
HSRP
No tuning—2 seconds—distribution
Use TRACKING feature
OSPF
Hello timer 1 sec, Dead timer 3 sec
Recovery 6 seconds across backbone
EIGRP
Hello timer 1 sec, Hold timer 3 sec
Recovery 3 seconds across backbone
STP
Tune “diameter” to 2 on root switch
Improves recovery 50 sec to 15 sec
Avoid STP loops and tuning!

14. The Hub and Router Model
Hierarchical and modular
Deterministic for troubleshooting
L3 features and Cisco IOS™ advantages
Addressing scalability
Multiprotocol routing and support
Middleware, DLSw+, GNS proxy
Proxy ARP, DHCP relay, debug
Basis of many large Intranets

15. Traditional Router and Hub Campus
Workgroup Server
Workgroup Server
Workgroup Server
Building A
Building B
Building C
Access
Layer
Hub
Hub
Hub
Distribution
Layer
The L2/L3 design provides for effective redundancy and load balancing.
Workgroups have redundant connectivity to the distribution layer using the ISL trunking protocol. ISL trunking provides an efficient way to configure one or more workgroups on a wiring-closet switch. ISL trunking also provides an effective way for workgroups to span more than one switch.
In the L2/L3 model enterprise servers are centralized with connectivity at the core layer. Access to all workgroups is by a single-hop, high-performance path.
Workgroup-level servers may attach at the distribution layer, or at the wiring-closet switch in the access layer.
Redundant connectivity to a switch domain (building) is provided by a pair of Catalyst 5000 switches with NFLS. Thus all workgroups have a redundant connection to the distribution layer, and in turn a redundant path to the core and out to the rest of the enterprise.
FDDI Dual Homed
Core
Layer
ATM
FDDI Backbone
Dual Homed
VLAN Trunk FE
FEC
E or FE Port
Token Ring Port
Enterprise
Servers
FDDI Port

16. VLAN Design Considerations
A VLAN is a flat-bridged network
Trunking and ATM LANE
Campus-wide VLAN model
Depends on 80/20 traffic pattern
Router-on-a-stick considerations
Useful tools for multilayer design

17. VLAN Technologies Y Z Workgroup Server Pink VLAN Client Pink VLAN
Green
VLAN
Workgroup
Server
Green VLAN
Catalyst
Switch X
Catalyst® 5000
with LANE Card
LANE Client (LEC)
Pink, Purple, Green A
ISL Attached
Enterprise Server B C D
ATM Switch
ATM
VLAN Trunk FE
Server
LANE Client (LEC)
Pink, Purple, Green
Workgroups:
Pink
Purple
Green
FEC
E or FE Port
Token Ring Port
FDDI Port
1134_04F8_c4 17

18. VLAN Trunking Protocols
ISL (Inter-Switch Link, used on FE)
Adds 30-bytes to the frame header
(SAID, Security Association ID)
Adds 16 bytes to the frame header
DISL (Dynamic ISL) point to point
Protocol over Fast Ethernet trunk
LANE (LAN Emulation)
Extending VLANs to ATM domain
VTP (VLAN Trunk Protocol)

19. Traditional Campus-Wide VLAN Design
Building A
Building B
Building C
Access
Distribution X
Core
Server
Distribution
Four Workgroups:
Blue
Pink
Purple
Green
Workgroup
Server Green
ISL Attached
Enterprise Server
Enterprise
Servers
1134_04F8_c4 19

20. Campus-Wide VLANs and Multilayer Switching
Building A
Building B
Building C
Access Layer
Distribution Layer
Core
Layer
FEC/ISL
Server
Workgroup
Server Green
Catalyst
Multilayer Switch
Four Workgroups:
Blue
Pink
Purple
Green X
Server
Distribution
FE Attached
Enterprise
Servers
FEC Attached
Enterprise
Server
1134_04F8_c4 20

21. MPOA Design Considerations
ATM to the wiring closet
L3 switching with header rewrite
MPOA handles IP unicast
Multiprotocol packet flow?
Multicast packet flow?

22. MPOA Campus Design Client Green VLAN Client Pink VLAN Access Switch
MPC X
Enterprise
Server MPC
Multiprotocol
Server MPS
Routes First Packet
of IP Unicast Flow
Access
Switch
MPC
ATM
VLAN Trunk FE
FEC
FEC Attached
Enterprise Server
E or FE Port
Token Ring Port
Enterprise Servers
FDDI Port

23. The Multilayer Design Model Must Solve These Issues
The new 80/20 traffic pattern
IP mobility (use DHCP)
Optimal use of multilayer switching
Recovery for L2 and L3 failures
Fast deterministic convergence
High-performance server farms
Scaling bandwidth
Ethernet and ATM backbones

24. Benefits of Modular Design
Wiring
Closet = Access
Load Balancing and Redundancy to Wiring Closet
Scalable Trunking FE, FEC, GE, GEC
Fast Failover with Uplink Fast and HSRP
L3, L4 Switching (=Routing) Intelligent Routing Protocols and Services, Fast Failover, Manageability
Layer 2
Switch
Ethernet Trunking
Up the Riser
Layer 3
Switch = Router
Distribution
Redundancy and Load Balancing
across Multiple Paths
FE-ISL or .1Q
FEC
E or FE Port
Campus Backbone
Frame or ATM
Layer 2 or Layer 3
Trunking Capacity Scales as You
Add Modules
Gig E or GEC
ATM OC-3
ATM OC-12

25. Generic Modular Campus Design
Building
Building
Building
Access
Layer
Layer 2
Switch
Distribution
Layer
Layer 3
Switch=Router
Backbone
Frame or ATM
Layer 2 or Layer 3
Core
Layer
Server
Distribution
Layer 3
Switch=Router
VLAN Trunk FE
FEC
E or FE Port
GigE or GEC
Layer 2
Switch
ATM
Server Farm

26. Multilayer Campus Design
L2 switching at wiring closet
L3 or L4 switching at distribution
L2 or L3 switching in backbone
Or ATM/PNNI in backbone
Hierarchical design scales
Address summarization

27. Multilayer Campus Distribution L3/L4 Building Blocks
L3 routing across backbone
Fast OSPF or EIGRP recovery
Load balancing up to six paths
L3/L4 at distribution layer
L2, L3, L4 switching in ASICs
Policy with no performance impact
L3/L4 features and services
Multiprotocol support and features
Broadcasts off backbone

28. Multilayer Switching— Hierarchical Campus
FEC Attached
Workstation
Building A
Building B
Building C
Access Layer
Catalyst 5000
L2 Switch
Distribution Layer
Catalyst
Multilayer Switch
Core
Layer
Catalyst
L2 Switch
ISL Attached
Building Server
ATM
VLAN Trunk FE
FEC
FEC Attached
Enterprise Server
E or FE Port
Token Ring Port
FDDI Port

29. Multilayer Model with Redundancy
Redundant building blocks
1000+ clients don’t lose connectivity
L3 routing across backbone
Load balancing
Fast deterministic failover
Redundant to wiring closet
Uplink Fast for L2
HSRP for L3

30. Redundant Multilayer Campus Design
North
West
South
Access Layer
Distribution Layer A B C D
Core
Layer
ISL Attached
Building Servers
The Catalyst 5000 switches with NFLS at the distribution layer provide redundant connectivity into the core.
Within the core high capacity trunks use Fast Ethernet or Fast EtherChannel depending on bandwidth requirements.
The Cisco IOS provides load balancing and fast failover across the core for network protocols. X Y
ATM
VLAN Trunk FE
FEC
E or FE Port
FEC Attached
Enterprise Server
Enterprise Servers
Token Ring Port
FDDI Port

31. Enterprise Server Farm Design
Server distribution block
Scalable bandwidth
Consistent diameter two hops
Deterministic and scaleable
HSRP redundancy
No default gateway issues
No IP redirect issues
Load balancing
Server-to-server traffic off backbone

32. Multilayer Model with Server Farm
North
West
South
Access Layer
Distribution Layer
Core
Layer V W B
Gigabit Ethernet
Gigabit Ethernet
ATM X Y
Server
Distribution
VLAN Trunk FE A
FEC
E or FE Port
Gigabit Ethernet
FEC Attached
Enterprise
Server
Token Ring Port
FE Attached
Enterprise Servers
FDDI Port

33. Server Attachment in the Multilayer Model
VLANs
A, B, C, D
Access Layer
Server M
Workgroup D
Distribution Layer
Server N
A, B, C, D
Core
Layer W X
ATM
HSRP
HSRP
Server
Distribution
VLAN Trunk FE
FEC
E or FE Port
FE Attached
Enterprise Servers
Gigabit Ethernet Y Z
FEC Attached
Enterprise
Server
Token Ring Port
FDDI Port

34. Wiring Closet Connectivity
Load balancing
Use what you pay for
Uplink Fast L2 convergence
Three second failover
HSRP L3 convergence
Two second failover

35. Redundancy with HSRP Access Layer ISL Trunks VLAN Multiplexing
Host A
Even Subnet
Gateway
Host B
Odd Subnet 11.0
Gateway
Host C
Odd Subnet 15.0
Gateway
Host D
Odd Subnet 17.0
Gateway
Access Layer
ATM
ISL Trunks
VLAN Multiplexing
Fast Ethernet or
Fast EtherChannel®
VLAN Trunk FE
FEC
E or FE Port
Cisco’s Hot Standby Router Protocol (HSRP) provides gateway redundancy for IP hosts. Two Catalyst 5000 switches with the RSM act together to provide the gateway redundancy.
If one Catalyst 5000 switch experiences a failure or a loss of connectivity, the other will automatically take over as gateway. The switch-over takes a few seconds; fast enough that most sessions will remain intact.
HSRP also supports load balancing. Multiple addresses can be configured to act as primary gateway to different groups of hosts. This feature is called Multiple HSRP (MHSRP).
Token Ring Port
FDDI Port
HSRP Primary
Even Subnets,
Even VLANs,
10, 12, 14, 16 X Y
HSRP Primary
Odd Subnets,
Odd VLANs,
11, 13, 15, 17

36. HSRP with Tracking Determine the STP path Load balancing
Define root bridges per VLAN
RSM1#
interface vlan 2
ip address
standby 1 ip
standby 1 priority 300 track
standby 1 preempt
RSM2#
ip address
standby 1 priority 200 track
VLAN 2
VLAN 3 B B
Root
VLAN 2
Root
VLAN 3
vlan 99
vlan 99

37. VLAN Trunking for Load Balancing
VLANs
10, 11
VLANs
12, 13
VLANs
14, 15
VLANs
16, 17 A B C D
F10
B11
F 11
B 10
F 12
B 13
F 13
B 12
F 14
B 15
F 15
B 14
F 16
B 17
F 17
B 16
F—Forwarding
B—Blocking
ATM
VLAN Trunk FE
ISL Trunks
VLAN Multiplexing
Fast Ethernet or
Fast EtherChannel
FEC
E or FE Port
Token Ring Port
FDDI Port X Y
STP Root
Even VLANs
10, 12, 14, 16
STP Root
Odd VLANs
11, 13, 15, 17

38. Uplink Fast Used for switches in the wiring closet
Changes the bridge priority and port/VLAN/cost parameter
Grouping port
Moves port directly from blocking state to forwarding state
No topology change will be generated
Generate proxy-multicast packets
Does not work with LANE
Limited VLANs to achieve fast convergence

39. VLAN Trunking with Uplink Fast Failover
VLANs
10, 11
VLANs
12, 13
VLANs
14, 15
VLANs
16, 17 A B C D
F10
B11
F 11
B 10
F 12
B 13
F 13
B 12
F 14
B 15
F 15
B 14
F 16
B 17
F 17
B 16 X
F—Forwarding
B—Blocking
ATM
VLAN Trunk FE
ISL Trunks
VLAN Multiplexing
Fast Ethernet or
Fast EtherChannel
FEC
E or FE Port
Token Ring Port
FDDI Port X Y
STP Root
Even VLANs
10, 12, 14, 16
STP Root
Odd VLANs
11, 13, 15, 17 Z

40. Scaling Ethernet Trunking
Switch, router, server connection
Load distribution
Ethernet bandwidth options
Fast Ethernet
Fast EtherChannel
Gigabit Ethernet
Gigabit EtherChannel
VLAN trunking with ISL or 802.1Q

41. EtherChannel Built on 802.3 FD standard
Provides 200FDX or 400FDX (or 2G or 4G)
Grouping 2/4 ports
Load balancing based on (X- or) on SA, DA addresses; for multicast address based on source address
GEC supported on Bladerunner
Support spanning tree (3.1, or better)
Only a software upgrade on the routers

42. EtherChannel Port-Aggregation Protocol (PAgP)
It runs on Fast EtherChannels only
PAgP to avoid misconfiguration
Four types of operation
On, desirable, auto, off

43. PAgP Operation PAgP will be enable on the channels
Auto < > Auto
Auto < > Desirable
Desirable < > Desirable

44. Scaling Ethernet Trunk Bandwidth
Best B
Good C OK
VLANs
1, 2, 3, 4, 5, 6
VLANs
1, 2, 3, 4, 5 ,6
VLANs 1 2 3
FEC ISL
VLANs
1, 2, 3, 4, 5, 6
400Mbps
FDX
Fast
Ethernet
ISL
1, 2
3, 4
5, 6 1 2 3
Fast
Ethernet
VLAN Trunk FE
FEC
E or FE Port
Token Ring Port
FDDI Port

45. Policy in the Backbone VLAN per policy VLAN per protocol
Logical or physical partition

46. Logical or Physical Partitioning of the Core
Domain A
Domain B
Domain C
Distribution
Layer
Workgroup
Servers
Core
Layer
VLAN
100
IP Subnet
VLAN
200
IPX Network BEEF0001 V W
Server
Distribution X Y
ATM
VLAN Trunk FE
FEC
E or FE Port
Novell IPX®
File Servers
Token Ring Port
IP Servers
WWW
FDDI Port

47. Multilayer with LANE Backbone
Ethernet up the riser
Redundancy recommendations
Two ELANs in the backbone
SSRP for LES/BUS and LECS
Dual PHY connectivity
Same building blocks
Hierarchical ATM and PNNI

48. Multilayer Model with ATM LANE Core
Domain A
Building A
Domain B
Building B
Domain C
Building C
Distribution
Layer
OC-3 or OC-12 Uplinks
Cisco LECS
Primary
Core Layer
ATM LANE
LightStream® 1010
ATM Switch
LECS Backup
LS1010
ATM Switch
LECS Backup
The L2/L3 hierarchical model works equally well with an ATM backbone. The logical design of networks and subnets remains the same.
Today ATM backbones are typically implemented using LAN Emulation or LANE. Native ATM enterprise servers attach as ATM LANE clients to an ATM switch in the core.
In this picture Ethernet or fast Ethernet servers connect to the backbone by a Catalyst 5000 switch which acts as a LANE client to the ATM core.
Alternatively, the ATM switch in the backbone can be combined with the Ethernet switch in a single Catalyst 5500 switch.
Trunking within the core can be OC3 or OC ATM PNNI routing also supports load balancing over multiple links between adjacent ATM switches.
Server
Distribution
Catalyst 5000
LES/BUS Primary
Catalyst 5000
LES/BUS Backup X Y
ATM
VLAN Trunk FE
FEC Attached
Enterprise Server
FEC
E or FE Port
Enterprise
Servers

49. IP Multicast Forwarding and CGMP/IGMP
NO CGMP
With CGMP
PIM
PIM
IGMP
Request
for Group 1
Multicast Group 1
Multicast Group 1
CGMP
Multicast Frames
Forwarded to Every Switch Port in a VLAN
IGMP
Request
for Group 1
A B C D
A B C D
CGMP prevents flooding of unnecessary multicast traffic
Uses standard IGMP on user end-station
Router optimizes switch multicast forwarding table
1134_04F8_c4 49

50. IP Multicast Routing Protocol Roundup
DVMRP
CBT
Dense Representation Only
First Generation Technology
PIM Interoperation
Protocol-Dependent
Scalability Limitations
Sparse Representation
Increased Efficiency
Improved Scalability
Limited Commercial Deployment
MOSPF
PIM Dense and Sparse-Mode
Dense Representation Only
Routing Protocol-Dependent
Not Efficient
Scalability Limitations
Limited Industry Experience
Dense or Sparse Representation
Scalable
Efficient
Not Routing Protocol-Dependent
Suitable for All Environments

51. Multicast Firewall and Backbone
Clients for Multicast
A Only
Clients for Multicast
B Only
Clients for Multicast
C Only
Distribution
Layer
B Only
C Only
A Only
Multicast VLAN 100
IP Subnet
Unicast VLAN 200
IP Subnet
Server
Distribution X
ATM
VLAN Trunk FE
FEC
E or FE Port
Gigabit Ethernet
Token Ring Port
Multicast
Server Farm
Unicast
Server Farm
FDDI Port

52. WAN Distribution Building Block
Redundant firewall example
Attaches to backbone
Peer module across backbone

53. WAN Distribution Building Block
Layer
Core
Layer
Multilayer Switch as Inner
Firewall Router
Bastion Hosts
Web Servers
Firewall Devices
in the DMZ
WAN
Distribution
ATM
Outer Firewall
Routers
VLAN Trunk FE
FEC
E or FE Port
Token Ring Port
FDDI Port
To Internet Service Providers (ISPs)
1134_04F8_c4 53

54. Spanning Tree Boundary
Bridge 1 protocol DEC
int fast 0/0.1
ip address
standby ip
encap ISL
bridge-group 1
Bridge 1 protocol DEC
int fast 0/0.1
ip address
standby ip
encap ISL
bridge-group 1
Bridge 1 protocol DEC
int fast 1/1
bridge-group 1

55. RSM Two SAGE channels to bus
Maximum 400 Mbps throughput and 170K pps optimum switching
Logical interface per VLAN
Multiprotocol network, routing protocols, HSRP
NFFC—IP switching in hardware

56. L3 Switching with the NFFC
Router multicasts its MAC address/VLAN
First packet is candidate packet
Switch would enable the flow once the packet is back from the router
Packets in flow switched by NFFC
Host A
Host B
VLAN 2
VLAN 3

57. L3 Switching with the NFFC
Flow is a unidirectional sequence of packets between two end points with respect of the transport layer
NFFC parses packets in the hardware as far as transport layer
MLSP (MultiLayer Switch Protocol) used to inform switches of the routing and access-list changes

58. L3 Switching with the NFFC
NFFC (NetFlow Feature Card)
Mounted on SUPIII, used with RSM
NetFlow data collection to flow level
Policy (ACL) to flow level

59. L3 Switch Specialization
Common IOS Services
Routing: OSPF, EIGRP
Multicast: PIM BOOTP and DHCP
VLAN HSRP
Load Balancing
Management: CDP, NTP
Access Lists
TACACS +
Wiring Closet/Distribution
Backbone/Data Center
LAN/WAN Integration
Port Density
Scalability
Advanced Services
Catalyst 5500
Catalyst 8500
Cisco 7500
Specialized Services(Platform Specific)
Cisco 7500
Catalyst 5500
Catalyst 8500
Multiprotocol Routing
SNA Integration
NetFlow Accounting
Extensive IP QoS
Voice, Security
Encryption/Compression
1-3 Mpps IP Routing
Multiprotocol Routing
NetFlow Accounting
VLAN Architecture
QoS Enablers
5-24 Mpps IP, IPX and
IP Multicast Routing
QoS Enforcement
VLAN Aware
Per Flow Queuing
1134_04F8_c4 59

60. Catalyst 8500 Multilayer Switch Backbone or Data Center Distribution
Cisco IOS
Cisco Express Forwarding
Wire-Speed IP, IPX Switching
Cisco IOS Routing Protocols
Wire-Speed IP Multicast
Extensive QoS Capabilities
Access Control Lists
Catalyst Slot
Catalyst 8540
13 Slot
Chassis
Nonblocking fabric
Hot swappable line cards
Redundancy
Performance
10 Gbps to 40 Gbps switching fabric
Wire-speed (5-24 Mpps) throughput
Line Modules
10/100 , GE, FE/GE channel
OC-3, OC-12, OC-48 ATM and PoS Uplinks
1134_04F8_c4 60

61. ACME Campus Case Study (From Datacomm Shootout)
2200 stations
Six buildings
Enterprise server farm
Distributed departmental servers
Mixture of hubs, cabling, routers

62. Case Study Solution High-Performance L3 Backbone
L3 switched backbone
Catalyst 8540 based
Non-blocking switching
Load balancing within backbone
Hig-capacity trunking
FE, FEC, GE, GEC
HSRP for server farms

63. Case Study—Collapsed BackboneM1
RD1 and RD2
A1 and A2
Access
Layer
Catalyst
55xx
Distribution
Layer
Catalyst
5505
Servers
Servers
Servers M2
Catalyst
8540
VLAN Trunk FE
FEC
FE Attached
Enterprise
Servers
FEC Attached
Enterprise
Server
E or FE Port
Gigabit Ethernet

64. M2 Module: Non-Blocking
Backbone and Enterprise Server Farm
Catalyst 5505
Layer 2 Switches (6)
96 Ports 10/100
Two Subnets per Switch
Access
HSRP
Uplink Fast
GE Trunk to M2
GE Trunk to M2
FEC Trunk to A1
FEC Trunk to A1
FE Trunk to RD1
FE Trunk to RD1
Catalyst
8540
Catalyst
8540
Enterprise
Server Farm HSRP
To WAN
FE Attached
Enterprise
Servers
FEC Attached
Enterprise
Server
VLAN Trunk FE
FEC
E or FE Port
Gigabit Ethernet

65. Advantages of the Multilayer Model
Scales as you add modules
Performance scales
Addressing scales
Fast deterministic convergence
L3 routing across backbone
Uplink Fast and HSRP to wiring closet
Load balancing
Use what you pay for

66. 1134_04F8_c4 66