Various models of Cisco Catalyst 4948 switch : Layer 3 ,  trunking , link aggregation & ACL support

Posted on 2009-02-19
Last Modified: 2012-05-06
Are there several models of the Catalyst 4948 ?  

I'll need a 48 port gigabit Cisco switch that

a) provide Layer 3 support (so that I can define ACLs to filter traffic between
    our DMZ and other backend/production subnets

b)scalable : I need 90 ports currently but there could be plans for expansion, thus
   more ports will be needed in future.  Can I just trunk 2 or 3 or more of the 4948
   switches together (using 2xRJ45 ports) to scale them for more ports.  Is there
   a limit as to how many of the switches that could be trunked together?
   I usually hear that Fibre channel ports are used to trunk two switches together,
   is there any shortcoming of trunking two switches using RJ45 LAN Cat 6 cables?

c)Some of our VMWare blade servers may need a total aggregate of 2 or 3 Gbps
   bandwidth : which of the 4948 models support this link aggregation (802.?) ie
   we connect up 2 NIC ports on a server to the switches' port to get a bigger
   aggregate bandwidth throughput

d)Lastly someone ever told me it's possible to assign an IP address to a Layer 2
   switch's port by creating a VLAN, assign the VLAN to a Layer 2 switch port
   & then assign an IP addr to that VLAN : let me know the exact commands (step
   by step)  on  how to go about setting this up

Question by:sunhux
    LVL 3

    Accepted Solution

    Yes there are different models of 4948 but they only relate to the image that is loaded and other options, not to the number of ports. You can use any variety of Cisco switches to accomplish what you are talking about, is there a reason for the 4948? 3560G and 3750G both have the same throughput and there are -E versions with 10Gig uplinks that you could use between switches. You could alos look at a blade based solution such as the 4500 series or 6500 series based on rate of expansion. If you are planning to add a significant amout of switches, you may want to consider doing a 2 layer model and incorporate a distribution layer. In order to set up a VLAN and then assign switchports do the following from configuration mode on the switch.

    Create the VLAN (substitute vlan # and ip with yours)

    vlan 10
    ip address
    no shut

    Assign Interface to VLAN (substitute vlan # and interface with yours) Repeat as necessary.

    interface f0/1
    switchport mode access
    switchport access vlan 10
    no shut

    Author Comment

    Thanks very much.

    Are the 3750G and 3650G models layer 3 switches?  I need to be able to create
    ACL and possibly do some routing

    Can the 3750g and 3650g support the following (link aggregation) :
    c)..... link aggregation (802.?) ie  we connect up 2 NIC ports on a server to the switches'
       port to get a bigger aggregate bandwidth throughput

    are the two models you suggested of lower cost than the 4948?

    I'm only looking at single U models and not the chassis type as our rack is short of
    space or mounting

    Lastly, can I get one of the 4948 and then get two of the 3xxx models suggested to
    trunk them together (to enjoy the 10Gbps uplink) and possibly the 3xxx is cheaper
    (enjoy the cost benefits)   as 4948 is true Layer 3?

    Author Comment

    Also, what's the differences between the images : what extra functionalities
    the better images provide, if you can quote a few as I need to determine the
    exact model that we need to get.

    Thanks v much
    LVL 3

    Assisted Solution

    All three are Layer 3,  the 3750 and 3560 both support at least 802.3ad link aggregation like the 4948. Both the 3560 and 3750 have a fixed configuration though and only one power supply. the 4948 has two modular power supplies but costs about double. If you are looking for 10Gig uplinks, you will want the 3560-E version or 3750-E as the G version is just all Gigabit ports. You will still want the X2 modules for any of the 3 to do 10Gig. Any of these can be trunked together. Any of the three will do any of the routing protocols like OSPF or EIGRP based on the image you have loaded.

    Author Comment


    So if I get the 3560-E  or 3750-E, it's all 48 port gigabit ports only
    and to get the 10Gbps uplink,  will still need to get the X2 modules,
    is this right?  Is this 10Gbps uplink fibre port or just the plain Cat 6
    RJ45 cable?
    LVL 3

    Assisted Solution

    You are correct. They have not released an X2 module that is straight cat6, only the proprietary copper good for 15m or fiber options. They are starting the cat6 modules with the SFP form factor for the Nexus line.
    LVL 3

    Assisted Solution

    In addition, if you don't need all 48 ports, they make a 24 port model of each.

    Featured Post

    What Should I Do With This Threat Intelligence?

    Are you wondering if you actually need threat intelligence? The answer is yes. We explain the basics for creating useful threat intelligence.

    Join & Write a Comment

    As companies replace their old PBX phone systems with Unified IP Communications, many are finding out that legacy applications such as fax do not work well with VoIP. Fortunately, Cloud Faxing provides a cost-effective alternative that works over an…
    PRTG Network Monitor lets you monitor your bandwidth usage, so you know who is using up your bandwidth, and what they're using it for.
    Here's a very brief overview of the methods PRTG Network Monitor ( offers for monitoring bandwidth, to help you decide which methods you´d like to investigate in more detail.  The methods are covered in more detail in o…
    This video gives you a great overview about bandwidth monitoring with SNMP and WMI with our network monitoring solution PRTG Network Monitor ( If you're looking for how to monitor bandwidth using netflow or packet s…

    728 members asked questions and received personalized solutions in the past 7 days.

    Join the community of 500,000 technology professionals and ask your questions.

    Join & Ask a Question

    Need Help in Real-Time?

    Connect with top rated Experts

    17 Experts available now in Live!

    Get 1:1 Help Now