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Catalyst 3750-X vs 4948


We are trying to decide if we should use Catalyst 3750 or 4948 to do switching and routing in a data centre.

Previously some reasons for buying 4948 have been redundant power supplies and non-blocking switches.

Now with the new Catalyst 3750-X coming out that has both those features, which advantages do you see for buying 4948?

Thanks in advance for your help!

Best regards,


Leo Laohoo
VIP Community Legend

Trying to find a reason why one prefers a 4948 against the 3750X ... Nope, can't think of one. 

Stumbled late into this discussion, but it is still valid as the 4948 series still whips the pants off much of the "currently new" product line.  One thing I have noticed is an extremely high rate of failure in 3750X switches when it deals with stacking failures.  There are some extreme design issues there, especially with the power staking.  This is purely from a personal experience, 3750Xs tend to fail every 1 to 3 years or exhibit some oddity often leading to an RMA.  4900s on the other have seem to be rock solid, more of a data center grade build than wiring closet grade.  Have never seem one fail that I have deployed.  I tried to research the numbers, and see conflicting or incomplete values on the 3750x series from data sheets and such, but an sure someone from the Cisco side can chime in with hard numbers. So here is what my personal experience boils down to, if the number one priorities are reliability and consistent performance go for the 4900 series - if it is that single CLI management interface then go with the 3750X.  Again, this is a personal experience, but it seems that the 4900 team was much more stability and ruggedness focused.


4948 back plane, buffers, queues....

    4948 = 96Gbps switching fabric,   16MB shared buffer, 72Mpps forwarding in layer 2 and 3 mode, 512 ingress and egress policers, 6 microsecond port-to-port latency, 2000 packet max input queue, up to 8 queues per port

    3750X = 160Gbps switching fabric (only 64Gbps through the stack plane), 16MB shared buffer, 101Mpps (layer 2, 3 not advertised), 64 ingress and egress policers, 200 packet max input queue, 6 to 19 microsecond forward latency port-to-port (independent test show 3750X exhibits much more variance on port-to-port latency than 4948s, especially when stacking is involved).


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Well, the difference is, the 4900 series are basically non-chassis 4500s.  I agree they tend to be more "industrial" strength or carrier grade.

Leo Laohoo
VIP Community Legend

Geez.  This is an old thread.  :)


Over the years, there's only one reason why I want to stick to 3750X:  Stable IOS code.  


Another reason is redundancy:  If a switch member of the stack fails, then you can just replace this and have little impact.  


There are, however, extreme cases why I'd choose 4900 over 3750X.

@Leo, I have actually found the code to be the same on both.  4500s tend to be deployed in many more large campus environments that actual push the code on the load and configuration variation much further.  Because of that,  I would tend to think that since both follow the same 15.0 and 12.2 OS paths, the stability of the hardware and more heavily scrutinized, tried and true, OS would be the 4900 (based on 4500 Sup V that has been out for years).   

I think the best use have to do more with what they were really made for.  The 4948 was intended to be a top-of-rack server switch or small campus core. The 3750X is really a user access switch, wiring closet switch.  Both are great switches, other than hardware stability and durability form my personal experience.  So, if I was building a core that I needed to be rock solid or top of rack where huge amount of concurrent frames will be passed across many ports, really push the store and forward limits of the buffers, 4900 series would always be my choice.  If I need a user switch, PoE, and have to worry about limited CLIs to administer, 3750 stacks are great.       


One thing to remember about Cisco is that they 'pit' their development teams against one and other, so to speak.  The 2960SX, 2975, and 3750 are another set of examples.  The 2975 is the layout of the 3750, while only layer 2.  POE2 and stackability is cheaper than the 3750, while the 2975SX came out with many of the same features and sharable power.  This comes from the switchlines being sustained by the success of the line they produce, and each in its own business 'silo.'

Therefore, two switch sets can have nearly identical feature sets, but be two different lines.  What we did was look at the features we use, then looked if Cisco was committed to the line, and finally whether there was feature we may use in the future. 

Thanks for the replies!

One thing that I have noticed is that the 3750 (at least the older versions) only support 26 VRFs, whereas the 4948 supports 64.

Are you aware of any other major differences?

Best regards,


Jon Marshall
VIP Community Legend

net-harry wrote:

Thanks for the replies!

One thing that I have noticed is that the 3750 (at least the older versions) only support 26 VRFs, whereas the 4948 supports 64.

Are you aware of any other major differences?

Best regards,



There are quite a few differences but whether or not they are important only you can say really. Have you done a side by side comparison of the data sheets -

3570 datasheet

4948 datasheet


Hi Jon,

Yes, I have compared the data sheets, but I find it difficult to find less obvious feature differences.

I have used the Cisco Software Advisor Tool to check the software differences, but some of the features that are listed as present in only seems to be available also in the other.

The software that I used were the latest available (Cisco Catalyst 3750E running 12.2(53)SE1 and Cisco Catalyst 4948 Running 12.2(53)SG1). Features that were present on both are not listed.

Software features that 3750E has but not 4948

Access Switch Device Manager (SDM) Template

ANSI TIA-1057 LLDP - MED Location Extension

Auto Smart Ports

Cisco IOS Software Activation

Cisco IP Phone Support

Cisco StackWise Technology


Client Information Signalling Protocol (CISP)

Common Session-ID logging enhancement

Configurable IGMP Leave Timer

Cos/DSCP exchange using LLDP

Critical VLAN with multi-auth

DHCP - Server Port Based Address Allocation

DHCP - Configurable DHCP Client

DHCP - DHCPv6 Relay Agent notification for Prefix Delegation

DHCP - DHCPv6 Individual Address Assignment

DHCP - DHCPv6 Server SNTP, NIS, NIS+, Refresh Timer options

DHCP - DHCPv6 Server Stateless Auto Configuration

DHCP Client Option 12

DHCP Snooping Option 82 enhancement for circuit-id string

DHCPv6 - Relay - Reload persistent Interface ID option

DHCPv6 Client Information Refresh Option

DHCPv6 Ethernet Remote ID option

DHCPv6 Repackaging

Embedded Event Manager (EEM) 2.4

Enhanced Tracking Support

Fallback Bridging

Fast Stack Image Upgrade

GOLD - Generic Online Diagnostics

HSRP for IPv6

IEEE 802.1x - Auth Fail Open

IEEE 802.1X - Flexible Authentication

IEEE 802.1x Fallback support

IEEE 802.1X Multi-Domain Authentication

IEEE 802.1x Supplicant Support for EAP-FAST

IEEE 802.1x Supplicant Support for MD5

IEEE 802.1X Voice Aware Security Violations

IEEE 802.1x with User Distribution

IGMP Proxy

IGMP Querier

IGMP Snooping

IP Admission Policy MIB

IP over IPv6 Tunnels

IP Phone Enhancement - PHY Loop Detection

IP SLAs Additional Threshold Traps

IPv4/IPv6 Dual Stack

IPv6 Access Services: DHCPv6 Prefix Delegation

IPv6 Access Services: DHCPv6 Relay Agent

IPv6 Default Router Preference

IPv6 QoS: (Quality of Service)


LLDP Power Assignment

MAC Authentication Bypass

MAC Move

MLD Snooping

Multi-host Mode with EPM

Multicast Etherchannel Load Balancing

NAC - L2 IP with Auth Fail Open



NSF Awareness - BGP

NSF Awareness - OSPF

RADIUS Change of Authorization (CoA)

RADIUS Server Load Balancing

Smart Install

SRR (Shaped Round Robin)

Standalone MAB support

Support for 4096 VLAN IDs

Transparent Bridging

Trunk Failover

Trusted boundary (extended trust for CDP devices)

Unicast Mac Filtering

VLAN-ID Based MAC Authentication

VTP version 3

Webauth Enhancements

Weighted Tail Drop (WTD)

Software features that 4948 has but not 3750

8-Way CEF Load Balancing

802.3ah and CFM Interworking

AAA Broadcast Accounting

AAA DNIS Map for Authorization

AAA Resource Accounting

AAA Server Group Deadtimer

AAA Server Group Enhancements

AAA Server Groups Based on DNIS

ACL - Named ACL Support for Noncontiguous Ports on an Access Control Entry

ACL - Reflexive Access Lists

Additional Vendor-Proprietary RADIUS Attributes

AppleTalk 1 and 2

AppleTalk Access List Enhancements

AppleTalk Load Balancing

AppleTalk SMRP

Authentication Proxy Accounting for HTTP

AutoRP Enhancement

BGP Conditional Route Injection

BGP Configuration Using Peer Templates

BGP Cost Community

BGP Cost Community Support for EIGRP MPLS VPN PE-CE

BGP Dynamic Update Peer-Groups

BGP Hybrid CLI Support

BGP Increased Support of Numbered as-path Access Lists to 500

BGP Link Bandwidth

BGP Multipath Load Sharing for Both eBGP and iBGP in an MPLS-VPN

BGP Next Hop Propagation

BGP Policy Accounting

BGP Reduction in Transient Memory Usage

BGP Route-Map Continue Support for Outbound Policy

BGP Route-Map Policy List Support

BGP Support for Dual AS Configuration for Network AS Migrations

BGP Support for IP Prefix Import from Global Table into a VRF Table

BGP Support for Named Extended Community Lists

BGP Support for Sequenced Entries in Extended Community Lists

BGP Support for TTL Security Check

Bidirectional PIM

Boot Config

Call Home

Certification Authority Interoperability (CA)

CFM Outward Facing MEP on Switchports


Cisco Express Forwarding - SNMP CEF-MIB Support

Cisco IOS Scripting w/ Tcl

CiscoView Autonomous Device Manager (ADP)

Class Based Weighted Fair Queuing (CBWFQ)

Class-Based Policing

Class-Based Shaping


CNS - Configuration Agent

CNS - Event Agent

CNS - Image Agent

CNS - Interactive CLI

CNS Config Retrieve Enhancement with Retry and Interval

Command Scheduler (Kron)

Command Scheduler (Kron) Policy for System Startup

Committed Access Rate (CAR)

Community Private VLAN

Config Change Tracking Identifier

Configuration Rollback Confirmed Change

Control Plane Policing (CoPP)

CoS Mutation

Debounce Timer per Port

Default Passive Interface

DHCP Client

DHCP Option 82 Pass Through

DHCP Proxy Client

DHCP Relay Agent Support for Unnumbered Interfaces

Display SAP by Name

DLR Enhancements: PGM RFC-3208 Compliance

DRP Server Agent

Easy IP (Phase 1)


Embedded Event Manager (EEM) 2.0

Enhanced High System Availability

EtherChannel Enhancement - Single Port Channel

EtherChannel Layer 4 Distribution

Ethernet Operations, Administration, and Maintenance (OAM)

Extended ACL support for IGMP to support SSM in IPv4


FHRP - Enhanced Object Tracking of IP SLAs

FHRP - EOT integration with EEM

Firewall Authentication Proxy

Flex Link VLAN Load-Balancing

Flex Links

Flow-Based WRED

Forced 10/100 Autonegotiation

Gateway Load Balancing Protocol (GLBP)

Generic Routing Encapsulation (GRE)

Generic Routing Encapsulation (GRE) Tunnel Keepalive

Generic Routing Encapsulation Tunnel IP Source and Destination VRF Membership (PXF Based)

Generic Traffic Shaping (GTS)

HSRP - Hot Standby Router Protocol and IPSec

HSRP support for ICMP Redirects

HSRP support for MPLS VPNs

HTTP TACAC+ Accounting support


IEEE 802.1x - Wake on LAN Support

IEEE 802.1x Guest VLAN

IEEE 802.1x Private Guest VLAN

IEEE 802.1x Private VLAN Assignment

IEEE 802.1x Radius-Supplied Session Timeout

IGMP Version 3 - Explicit Tracking of Hosts, Groups, and Channels

Inline Power Auto Negotiation

Inline Power Management

Interface Index Persistence

Interfaces MIB: SNMP context based access

IP Event Dampening

IP Multicast over 1483 VC Mux Encapsulation on ARMII

IP Precedence Accounting

IP Precedence for GRE Tunnels

IP SLAs - DLSW+ Operation

IP SLAs - History Statistics

IP SLAs - LSP Health Monitor with LSP Discovery

IP SLAs - SNA LU2 Echo

IP SLAs - SNMP Support

IP SLAs - VoIP Threshold Traps

IP SLAs for MPLS Pseudo Wire (PWE3) via VCCV

IP SLAs Sub-millisecond Accuracy Improvements

IP Unnumbered for VLAN-SVI interfaces

IPv6 Bidirectional PIM

IPv6 Multicast

IPv6 Multicast: Address Family Support for Multiprotocol BGP

IPv6 Multicast: Bootstrap Router (BSR)

IPv6 Multicast: Explicit Tracking of Receivers

IPv6 Multicast: MLD Access Group

IPv6 Multicast: Multicast Listener Discovery (MLD) Protocol, Versions 1 and 2

IPv6 Multicast: PIM Accept Register

IPv6 Multicast: PIM Embedded RP Support

IPv6 Multicast: PIM Source-Specific Multicast (PIM-SSM)

IPv6 Multicast: PIM Sparse Mode (PIM-SM)

IPv6 Multicast: Routable Address Hello Option

IPv6 Multicast: RPF Flooding of Bootstrap Router (BSR) Packets

IPv6 Multicast: Scope Boundaries

IPv6 Routing: IS-IS Multitopology Support for IPv6

IPv6 Routing: IS-IS Support for IPv6

IPv6 Services: Cisco Discovery Protocol (CDP) - IPv6 Address Family Support for Neighbor Information

IPv6 Stateless Auto-configuration

IPv6 Switching: CEFv6 Switched Automatic IPv4-compatible Tunnels

IPv6 Switching: CEFv6 Switched Configured IPv6 over IPv4 Tunnels

IPv6 Switching: CEFv6 Switched ISATAP Tunnels

IPv6 Tunneling: Automatic 6to4 Tunnels

IPv6 Tunneling: Automatic IPv4-compatible Tunnels

IPv6 Tunneling: IPv6 over IPv4 GRE Tunnels

IPv6 Tunneling: ISATAP Tunnel Support

IPv6 Tunneling: Manually Configured IPv6 over IPv4 Tunnels

IPv6: Anycast Address

IPX Access Control List Violation Logging

IPX Access List Plain English Filters

IPX Named Access Lists



ISSU (IOS In-Service Software Upgrade)

ISSU - 802.3ah OAM Support

L2PT - Layer 2 Protocol Tunneling on Trunk Ports

Loadsharing IP packets over more than six parallel paths

Lock and Key

Logging to Local Nonvolatile Storage (ATA Disk)

Low Latency Queueing (LLQ)

MAC Address Notification

Manual Certificate Enrollment via TFTP

Memory Threshold Notifications

Modular QoS CLI (MQC)

MPLS VPN - Inter-Autonomous System Support


MPLS VPN - Route Target Rewrite

MSDP compliance with IETF RFC 3618

Multi-protocol BGP (MP-BGP) - MPLS VPN

Multicast Fast Switching Performance Improvement

Multicast Routing Monitor (MRM)

Multicast-VPN: Multicast Support for MPLS VPN

Netconf access for Configuration over BEEP


Next Hop Resolution Protocol (NHRP)

Novell IPX


NSF - Graceful Restart (GR) and Non Stop Routing (NSR) for IS-IS

NSF/SSO (Nonstop Forwarding with Stateful Switchover)

NSF/SSO - 802.3ah OAM Support

NSF/SSO Support in CFM 802.1ag/1.0d

On Demand Routing (ODR)

OSPF Area Transit Capability

OSPF Flooding Reduction

OSPF Incremental Shortest Path First (i-SPF) Support

OSPF Limit on Number of Redistributed Routes

OSPF Link State Database Overload Protection

OSPF Link-local Signaling (LLS) Per Interface Basis

OSPF MIB Support of RFC 1850 and Latest Extensions

OSPF On Demand Circuit (RFC 1793)

OSPF Packet Pacing

OSPF Sham-Link Support for MPLS VPN

OSPF Shortest Paths First Throttling

OSPF Stub Router Advertisement

OSPF Support for Fast Hellos

OSPF Support for Forwarding Adjacencies over MPLS Traffic Engineered Tunnels

OSPF Support for Link State Advertisement (LSA) Throttling

OSPF Support for Multi-VRF on CE Routers

OSPF Support for Unlimited Software VRFs per Provider Edge (PE) Router

OSPF Update Packet-Pacing Configurable Timers

Out-of-band Management Port

Pagp/UDLD/LACP L2 tunneling

PBACL (Policy Based Access Control Lists)

Performance Enhancements for IOS ACL

Periodic MIB Data Collection and Transfer Mechanism

PGM Host

Port Security on Etherchannel Trunk Port

Pragmatic General Multicast (PGM)

Pre-fragmentation For Ipsec VPNs

Private VLAN Promiscuous Trunk Port

Private VLAN Trunk Ports

QoS Policy Propagation via Border Gateway Protocol (QPPB)

QoS Priority Percentage CLI Support

RADIUS Attribute 44 (Accounting Session ID) in Access Requests

RADIUS for Multiple User Datagram Protocol Ports

RADIUS Tunnel Attribute Extensions

Redundancy Facility Protocol

Reliable Delivery and Filtering for Syslog

REP - (Resilient Ethernet Protocol)

Response Time Reporter (RTR)

Response Time Reporter (RTR) enhancements

Reverse Route Injection (RRI)

RGMP - Router-Port Group Management Protocol

Role-Based Access Control CLI commands

Router Security Audit Logs

Router Security Audit Manageability

RTP Header Compression

Selective Packet Discard (SPD)

Selective Virtual-Access Interface Creation

Silent Operation Mode

SNMP Support for BGP Policy Accounting

SNMP Support over VPNs - Context Based Access Control

Source Specific Multicast (SSM) - IGMPv3,IGMP v3lite, and URD

Source Specific Multicast (SSM) Mapping

Span Enhancement: Packet Type and Address Type Filtering


SSO - IGMP Snooping

SSO - Multilink PPP (MLP)


Standby Supervisor Port Usage

Sticky Port Security

Sticky Port Security on Voice VLAN

Suppress BGP Advertisement for Inactive Routes

SVI (Switch Virtual Interface) Autostate Exclude

Switch Port Analyzer (SPAN) - CPU Source

System Logging - EAL4 Certification Enhancements

Tacacs SENDAUTH function

Triggered RIP

Trusted Root Certification Authority

Tunnel Type of Service (TOS)

UDLR Tunnel ARP and IGMP Proxy

Uni-Directional Link Routing (UDLR)

Unidirectional Ethernet

User Maximum Links

Vendor-Specific RADIUS Attributes

Virtual Router Redundancy Protocol (VRRP)

Virtual Trunking Protocol (VTP) - Pruning

VLAN MAC Address Filtering

Warm Reload

WCCP Version 2

Weighted Fair Queueing (WFQ)

Weighted RED (WRED)

Best regards,


Hello Harry,

as Jon has noted all depends from what is the use of devices:

if they are going to be used in a datacenter as L2 only switches and in an IPv4 only environment (just to make an example), a lot of the listed items are not of interest.

If you are going to use them for access layer and for the security policy of your company you would like to implement 802.1X authentication with some of the listed features that are missing on 4948 your choice can be done.

also the fact that C3750 are stackable and C49848 are not can be of value or not depending on the use

to be noted declared performances are close.

Hope to help