This paper will provide an insight into the architecture of the Cisco® Catalyst® 6500 family,
including supervisor engines, line cards, chassis, and other components.
Cisco Catalyst 6500 Chassis
The Cisco Catalyst 6500 is a modular chassis family supporting a range of line-card options for
all customer network deployments. Its performance scales up to 400Mpps, providing one of the
highest performing switch products on the market today. It supports a range of chassis options
delivering from 3 to 13 slots. All chassis support redundant supervisor engines as well as
redundant power supplies. The chassis options are shown in Figure 1.
Figure 1. Cisco Catalyst 6500 Chassis Family
The Cisco Catalyst 6500 chassis family includes the following:
●
Cisco Catalyst 6503 Switch: Three-slot chassis supporting redundant power supplies,
redundant supervisor engines, and slots for up to two (2) line cards. NEBS L3 compliant.
●
Cisco Catalyst 6506 Switch: Six slot chassis supporting redundant power supplies,
redundant supervisor engines, and slots for up to five (5) line cards. NEBS L3 compliant.
●
Cisco Catalyst 6509 Switch: Nine slot chassis supporting redundant power supplies,
redundant supervisor engines, and slots for up to eight (8) line cards. NEBS L3 compliant.
●
Cisco Catalyst 6509-NEB Switch: NEBS based nine slot chassis supporting redundant
power supplies, redundant supervisor engines, and slots for up to eight (8) line cards.
This chassis also supports front to back airflow and is NEBS L3 compliant.
Cisco Catalyst 6509-NEB-A Switch: NEBS based nine slot chassis supporting redundant
power supplies, redundant supervisor engines, and slots for up to eight (8) line cards.
This NEBS based chassis differs from the first Cisco Catalyst 6509-NEB in that it can
support the new Cisco Catalyst 6500 Series Supervisor Engine 720 without any upgrades
to the chassis.
●
Cisco Catalyst 6513 Switch: Thirteen slot chassis supporting redundant power supplies,
redundant supervisor engines, and slots for up to twelve (12) line cards. This chassis
requires the Supervisor Engine 2 as the minimum version of installed supervisor.
NEBS L3 compliant.
Cisco has also recently introduced a new “E” series chassis that is designed to support a larger
power draw over the backplane and also drive higher power loads to each line-card slot. In all,
four new “E” series chassis have been announced:
●
Cisco Catalyst 6503-E Switch: Three slot chassis supporting redundant power supplies,
redundant supervisor engines, and slots for up to two (2) line cards. NEBS L3 compliant.
This chassis increases available power from 50A@42V (~2500W) to 80A@42V (~4000W).
●
Cisco Catalyst 6504-E Switch: Four slot chassis supporting redundant power supplies,
redundant supervisor engines, and slots for up to three (3) line cards. NEBS L3 compliant.
This chassis increases available power from 50A@42V (~2500W) to 80A@42V (~4000W).
●
Cisco Catalyst 6506-E Switch: Six slot chassis supporting redundant power supplies,
redundant supervisor engines, and slots for up to five (5) line cards. NEBS L3 compliant.
This chassis increases available power from 90A@42V (~4000W) to 350A@42V
(~12000W).
●
Cisco Catalyst 6509-E Switch: Nine slot chassis supporting redundant power supplies,
redundant supervisor engines, and slots for up to eight (8) line cards. NEBS L3 compliant.
This chassis increases available power from 90A@42V (~4000W)to 350A@42V
(~12000W).
Cisco Catalyst 6500 Backplane
The Cisco Catalyst 6500 incorporates two backplanes. From its initial release in 1999, the Cisco
Catalyst 6500 chassis has supported a 32-Gbps shared switching bus, a proven architecture for
interconnecting line cards within the chassis. The Cisco Catalyst 6500 chassis also includes a
second backplane that allows line cards to connect over a high-speed switching path into a
crossbar switching fabric. The crossbar switching fabric provides a set of discrete and unique
paths for each line card to both transmit data into and receive data from the crossbar switching
fabric. The first generation switching fabric was delivered by the switch fabric modules (WSC6500-SFM and WS-C6500-SFM2), each providing a total switching capacity of 256 Gbps. More
recently, with the introduction of the Supervisor Engine 720, the crossbar switch fabric has been
integrated into the Supervisor Engine 720 baseboard itself, eliminating the need for a standalone
switch fabric module. The capacity of the new integrated crossbar switch fabric on the Supervisor
Engine 720 has been increased from 256 Gbps to 720 Gbps. The Supervisor Engine 720-3B and
Supervisor Engine 720-3BXL also maintain the same fabric capacity size of 720 Gbps.
Depending on the Cisco Catalyst 6500 chassis, the crossbar switching fabric maps out a series
of fabric channels (otherwise known as paths into the crossbar) to each line-card slot in a slightly
different layout. Each chassis fabric layout is detailed in Table 1.
Cisco Catalyst 6503 1 and 2 2 and 3 2 and 3 WS-X67XX
Cisco Catalyst 6503-E 1 and 2 2 and 3 2 and 3 2 and 3
Cisco Catalyst 6504-E 1 and 2 2 thru 4 2 thru 4 2 thru 4
Cisco Catalyst 6506 5 and 6 1 through 6 1 through 6 1 through 6
Cisco Catalyst 6506-E 5 and 6 1 through 6 1 through 6 1 through 6
Cisco Catalyst 6509 5 and 6 1 through 9 1 through 9 1 through 9
Cisco Catalyst 6509-E 5 and 6 1 through 9 1 through 9 1 through 9
Cisco Catalyst 6509-NEB 5 and 6 1 through 9 1 through 9 1 through 9
Cisco Catalyst 6509-NEB-A 5 and 6 1 through 9 1 through 9 1 through 9
Cisco Catalyst 6513 7 and 8 1 through 13 1 through 13 9 through 13
Classic LineCard Slots
Single Fabric
Connected Line
Cards
Dual Fabric
Connected Line
Cards
line cards not
supported
In all but the thirteen slot chassis, each line-card slot has two channels in and out of the switching
fabric. The thirteen slot chassis has one fabric channel to each slot in slots 1 through 8 and two
fabric channels to each slot in slots 9 through 13. The crossbar switching fabric allows each line
card to forward and receive data to every other line card over a unique set of transmission paths.
Figure 2 shows the backplane and line-card connectors for a Cisco Catalyst 6509-E chassis.
The Cisco Catalyst 6500 supports two generations of fans. A new set of high-speed fans was
introduced with the announcement of the Supervisor Engine 720. New high-speed fans have
been designed for each Cisco Catalyst 6500 chassis, and their primary purpose is to provide
additional cooling for new generation line cards that draw more power and generate more heat.
If a Supervisor Engine 32, 720, 720-3B, or 720-3BXL is installed in the chassis, then the new highspeed FAN assemblies must be used. The FAN2 assemblies are used with the standard chassis,
and the E-Fan is used with the new E series chassis. These high-speed fans can also be used
with previous generations of the supervisor engine (1, 1A and 2). (See Figure 3 and Table 2.)
The Cisco Catalyst 6500 supports a range of AC and DC power supplies to suit a diverse range of
customer requirements. The power supplies supported are listed in Tables 3 and 4.
Table 3. Cisco Catalyst 6500 AC and DC Power Supplies
1000WAC (WS CAC-1000W) X X X
1300WAC (WS CAC-1300W) X X X
1300WDC (WS CDC-1300W) X X X
1400WAC (PWR 1400W-AC) X
2500WAC (WS CAC-2500W) X X X X X
2500WDC (WS CDC-2500W) X X X X X
3000WAC (WS CAC-3000W) X X X X X
4000WAC (WS CAC-4000W) X X X X X
4000WDC (PWR 4000DC) X X X X X
6000WAC (WS CAC-6000W) X X X X X
8700WAC (WS CAC-8700W-E) X X X X
Cisco
Catalyst
6506
Cisco
Catalyst
6509
Cisco
Catalyst
6509-NEB
Cisco
Catalyst
6509-NEB-A
Table 4. Cisco Catalyst 6500 E Series AC and DC Power Supplies
Power Supply (Part Number) Cisco Catalyst
6503-E
950WAC (PWR-950-AC) X
950WDC (PWR-950-DC) X
1400WAC (PWR-1400W-AC) X
2500WAC (WS-CAC-2500W) X X
2500WDC (WS-CDC-2500W) X X
2700WAC (PWR-2700W-AC) X
3000WAC (WS-CAC-3000W) X X
4000WAC (WS-CAC-4000W) X X
4000WDC (PWR-4000DC) X X
6000WAC (WS-CAC-6000W) X X
8700WAC (WS-CAC-8700W-E) X X
Cisco Catalyst
6504-E
Cisco Catalyst
6506-E
Cisco Catalyst
6509-E
Each of the power supplies provides a different set of operating characteristics. These are
summarized in Table 5.
Cisco
Catalyst
6513
Table 5. Cisco Catalyst 6500 Power Supply Characteristics
Power Supply Part Number AC Operation DC Operation Current Output
Power Supply Part Number AC Operation DC Operation Current Output
3000WAC WS-CAC-3000W 3000W @ 220VAC
1450W @ 110VAC
4000WAC WS-CAC-4000W 4000W @ 220VAC
30A circuit required
4000WDC PWR-4000-DC 1300W @ -48 to -60
6000WAC WS-CAC-6000W 6000W @ 2 x 220VAC
3000W @ 1 x 220VAC
3000W @ 2 x 110VAC
8700WAC WS-CAC-
8700W-E
8700W @ 3 x 220VAC
4200W @ 3 x 110VAC
6000W @ 2 x 220VAC
2800W @ 1 x 220VAC
2800W @ 2 x 110VAC
65.11 for 220VAC
28.21A for 110VAC
91.2A
91.2A
VDC
As noted in the table above, the 2500WAC, 2700WAC, 3000WAC, 6000WAC and 8700WAC
power supplies do not deliver full power in an environment running on 110VAC. The 2500W power
supply will deliver 1300W at 110VAC, the 2700W will deliver 1350W at 110VAC, the 3000W will
deliver 1450W at 110VAC,the 6000W will deliver 3000W with 2 x 110VAC circuits and the 8700W
will deliver 4200W with 3 x 110VAC circuits. It is also worth noting that current output is defined as
the amount of power made available by the power supplies to the chassis components.
Cisco Catalyst 6500 Supervisor Engines
The Cisco Catalyst 6500 supervisor engine is the primary module where the switch software is
loaded and all centralized control and data plane processes are performed. Control plane
functions refer to processes that are run in software, whereas data plane functions refer to
processes that are run in hardware.
The Supervisor Engine 32 supports a connection to the 32-Gbps shared bus and provides
forwarding rates up to 15Mpps. There is no support for a switch fabric in any form with the
Supervisor Engine 32. The new Supervisor Engine 720, 720-3B, and 720-3BXL integrate the
720-Gbps crossbar switch fabric onto the supervisor module itself and support a connection
into the 32-Gbps bus and a single 20-Gbps connection into the onboard crossbar switch fabric.
All Supervisor Engine 720 options support centralized forwarding rates up to 30Mpps and
distributed forwarding rates up to 400Mpps.
Supervisor Engine 32
The Supervisor Engine 32 is the most recent addition to the Cisco Catalyst 6500 supervisor
engine family. This supervisor engine provides an integrated PFC3B and MSFC2a by default.
The PFC3B provides hardware support for security and quality of service (QoS) based access
control lists (ACLs). QoS services supported on the PFC3B include ingress traffic policing as well
as classification of incoming data allowing the rewrite of class of service (CoS) bits in the Ethernet
header and type of service priority bits in the IPV4 header. Performance for these features is
supported at a rate of up to 15Mpps.
There are two versions of the Supervisor Engine 32 (Figure 4), one with 8 front Gigabit Ethernet
Small Form-Factor Pluggable (SFP) ports and the other with 2 x 10 Gigabit Ethernet front ports.
Both of these supervisor engines also have an additional 10/100/1000TX front port. Two USB
ports are also present on the front panel, one a type “A” and the other a type “B” USB port.
Figure 4. Supervisor Engine 32-8GE and Supervisor Engine 32-10GE
Cisco Express Forwarding is the forwarding architecture implemented in the Supervisor Engine 32
hardware. As with the Supervisor Engine 720, it also implements hardware registers and control
plane policing (CoPP) to limit the effect of denial of service attacks on the control plane. It comes
standard with 256MB of Bootflash on the switch processor (SP) side (which can be upgraded to
512MB) and 64MB of Bootflash on the route processor (RP) side. Memory (DRAM) size is 256MB
for both the RP and SP and NVRAM is 2MB.
Supervisor Engine 720
The Supervisor Engine 720 was introduced in 2003 and integrates the crossbar switch fabric,
Policy Feature Card 3 (PFC3), and Multilayer Switch Feature Card 3 (MSFC3) into the one
supervisor module. The PFC3 and MSFC3 are no longer optional.
The crossbar switching fabric on the Supervisor Engine 720 (Figure 5) increases backplane
capacity of the crossbar switch fabric from 256 Gbps to 720 Gbps. The crossbar switching fabric
supports connections to both the earlier fabric line cards, at 8 Gbps per fabric channel, and the
newer fabric line cards, at 20 Gbps per fabric channel. The Supervisor Engine720 also supports
classic line cards, thus providing total backward compatibility for all line-card generations. This
dual clocking capability preserves customer investment in previous line cards supporting
connections into the crossbar switch fabric.
Utilizing the new higher performance line cards with distributed forwarding allows a Supervisor
Engine 720 to scale switch performance to 400Mpps.
The Supervisor Engine 720 utilizes the Cisco Express Forwarding architecture to forward packets.
Support for up to 30Mpps of Layer 2 and 3 centralized switching of IP traffic is supported. Unlike
the earlier PFC1 and PFC2, IPX switching in hardware is not supported on the Supervisor Engine
720 PFC3. The Supervisor Engine 720, however, does still support IPX forwarding in software.
The Supervisor Engine 720 is based on a 600 MHz CPU for the switch processor (SP) and a
600 MHz CPU for the route processor (RP). This supervisor will support up to 1GB of DRAM for
the SP and up to 1Gb DRAM for the RP. The default SP bootflash is 512MB, the default RP
bootflash is 64 MB and the NVRAM size is 2MB.
The Supervisor Engine 720-3B is the most recent addition to the Supervisor Engine 720 family.
Architecturally it is the same as the original Supervisor Engine 720 in terms of the switch fabric
used and the backplane connections offered. It incorporates a new PFC3B, which increases the
functionality of the supervisor engine over its predecessor. It differs from the original Supervisor
Engine 720 mainly in functionality. Some of the features that differentiate it from the earlier
Supervisor Engine 720 include:
●
MPLS support in hardware
●
Support for EoMPLS
●
Support for Security ACL hit counters
●
Multipath URPF check now performed in hardware
●
Increased has efficiency (from 50 percent to 90 percent) for storing NetFlow entries
in the NetFlow table
●
Increased support for ACL labels from 512 to 4096
●
QoS policies can now be applied on tunnel interfaces
●
Layer 2 ACLs can be applied to IPV4 traffic
●
Support for matching on CoS and VLAN in ACLs is now supported
●
Support for up to 256K multicast routes in sparse mode
Supervisor Engine 720-3BXL
The Supervisor Engine 720-3BXL was introduced early in calendar year 2004. It is functionally
identical to the Supervisor Engine 720-3B, but differs in its capacity for supporting routes and
NetFlow entries. Up to 1 million routes can be stored in its forwarding tables and up to 256K
NetFlow entries can be stored in the NetFlow tables.
Multilayer Switch Feature Card (MSFC)
The control plane functions in the Cisco Catalyst 6500 are processed by the MSFC and include
handling Layer 3 routing protocols, maintaining the routing table, some access control, flow
initiation, and other services not found in hardware. Performance of the control plane is dependent
on the type and number of processes running on the MSFC. The MSFC3 can support forwarding
rates up to 500Kpps.
The MSFC3 is an integrated component on the Supervisor Engine 720, Supervisor Engine 720-3B,
and Supervisor Engine 720-3BXL. It is integrated onto all of the Supervisor Engine 720 options
along with the PFC3 and crossbar switch fabric. The MSFC3 is shown on a Supervisor Engine
720 in Figure 6.
Figure 6. MSFC3 on a Supervisor Engine 720
On the MSFC daughter card, the route processor (RP) is located on the MSFC itself. The RP
is responsible for a number of processes, including running the Layer 3 routing protocols,
performing address resolution, running ICMP, managing the virtual interfaces (that is, switched
virtual interfaces), and the Cisco IOS® Software configuration. The SP is primarily responsible
for running the Layer 2 protocols like spanning tree, VLAN Trunking protocol, Cisco Discovery
Protocol, and so on as well as programming the FIB tables onto the PFC.
While the multilayer switch feature card maintains the routing tables, it does not actively participate
in the forwarding of packets. The MSFC3 still participates in communicating with routing peers to
determine the network topology and maintain the routing tables. From the routing tables, the
MSFC3 will create a Cisco Express Forwarding table (also known as a Forwarding Information
Base—or FIB table) and push this down to the PFC and any DFCs present in the chassis.
The memory configurations across the different generations of supervisor (and MSFC)
are detailed in Table 6.
Table 6. Supervisor Engine and MSFC Memory Facts
Component Supervisor
Engine 328GE
SDRAM
Default SP:
256MB/1GB
Maximum RP:
256MB/1GB
Bootflash RP: 64MB
SP: 256MB
NVRAM SP: 2MB
RP: 2MB
* Note that 512MB of DRAM is standard on the Sup720 when ordering IOS 12.2(18)SXE or later
Supervisor
Engine 3210GE
SP:
256MB/1GB
RP:
256MB/1GB
RP: 64MB
SP: 256MB
SP: 2MB
RP: 2MB
Supervisor
Engine 720
SP:
512MB/1GB
RP:
512MB/1GB
RP: 64MB
SP: 512MB*
SP: 2MB
RP: 2MB
Supervisor
Engine 720-3B
SP:
512MB/1GB
RP:
512MB/1GB
RP: 64MB
SP: 512MB*
SP: 2MB
RP: 2MB
Supervisor
Engine 7203BXL
SP:
512MB/1GB
RP:
512MB/1GB
RP: 64MB
SP: 512MB*
SP: 2MB
RP: 2MB
Policy Feature Card
Complementing the MSFC is the policy feature card (PFC). The PFC is a daughter card that sits
on the supervisor base board and contains the ASICs that are used to accelerate Layer 2 and
Layer 3 switching, store and process QoS and security ACLs, and maintain NetFlow statistics.
The Policy Feature Card 3 (PFC3) is a standard inclusion with the Supervisor Engine 720 and
provides centralized forwarding performance up to 30Mpps. It contains a Layer 2 and a Layer 3
forwarding engine. The Layer 2 engine is responsible for:
●
Layer 2 MAC address lookups into the Layer 2 CAM table.
●
Looking into the packet headers to determine if this switching operation will be a Layer 2 or
a Layer 3 operation. If it is going to be a Layer 3 operation, then it will hand off the packet to
the Layer 3 engine for further processing.
The Layer 3 Engine is responsible for:
●
NetFlow Statistics collection.
●
Hardware based forwarding of IPv4, IPv6 and MPLS tagged packets
●
QoS mechanism for ACL classification, marking of packets, and policing (rate limiting).
●
Security mechanism for validating ACL rules against incoming packets.