Which would you choose: two 4948E switches or two 3750X switches?

[jstevens13]

I have to build a small standalone network.  The purpose of the network is to take mulicast MPEG2 video (at ~15 Mbps per stream) from encoder units and send it to MPEG2 processors and MPEG2 receiver/decoders. All would be on the same subnet so no routing needed and the receivers and processors would subscribe to the multicast streams that they needed at any particular time. 

All of the encoders and stream processors have GbE ports as well as some of the receivers.  Two of the receivers have 10GbE ports because they will be taking in most of the streams simultaneously.  Management of the switches would be done via the out of band Ethernet management ports.  Given the port count that I think I will need, I was looking at the following two configurations:

Option 1

Two 4948E switches.  Two of the four 10GbE  SFP+ ports on each switch are configured as etherchannel to uplink to the other switch.  One 10GbE port SFP+ on each switch is used to feed the MPEG2 receivers. 

Option 2

Two 3750X-48T switches with stackwise cables connecting them together.  Each switch would have the C3KX-NM-10G 10GbE (dual SPF+) card installed so that one 10GbE port on each switch is used to feed the MPEG2 receivers.

Option 2 seems appealing in that the two switches are managed as one logical unit and that the stack cable would provide a pretty high bandwidth between switches.  The thing that has me second guessing this option is that the 10GbE ports are on an option card and maybe that has a slightly higher tendency to fail than an integrated ports? 

I guess option 1 might be a little more straight forward in terms of recovery if one switch failed and someone besides me has to replace it years down the line.

It seems like both switches could handle the multicast traffic and the IGMP snooping that would be required.

Thoughts? 

. 

[Reza Sharifi]

I would do option 2 with stacking the 3750X together.  As for the uplink modules, I have deployed quite few of the 1Gig and 10Gig modules and have not seen any failure. The other option would be to use the new 3850 instead of the 3750X series.  The nice thing about the 3850 is that you can have up to 4 10Gig ports on the uplink module vs the 3750X is only 2.

Here is the data sheet for the 3850 series

http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps12686/data_sheet_c78-720918.html

Overall, the 2 series are somewhat similar, but there are some differences.

HTH

[jstevens13]

Reza, Dale, and Leo,

These are all excelent points.  With regards to the issue that Dale brought up about the max number of multicast and IGMP groups, this was something I had not considered after looking at it, it is something to be concenred about with regards to future growth.

Fortunatly, the suggestion that Reza and Leo made of the 3850 switch would aleaviate that issue a bit.  According to this document (PDF) the 3850 has an 8K limit for IGMP groups and multicast routes which should be fine for this project (assuming I'm understanding that correctly). 

And yes, I got a quote for the 3850 last night and it is exaclty the same price as the 3750X.  The added bonus of being able to put in a 4 port 10GbE card in each chassis is very nice as well. 

[Leo Laohoo]

Yea, wait 'til you stack them.

Sent from Cisco Technical Support Nintendo App

[Dale Miller · Accepted solution]

Removing budget contraints and looking at this from a technical point of view I would advise you to ensure the 3750 can handle the number of multicast and IGMP groups. Combined it supports 1k per any SDM template. Not sure the solution that is riding over this network and how many times the group may pass through the switch. Are you doing any encryption of the multicast or modification to the group IPs that would inflate the total amount seen on the switch? Note: the 1K limit is combined IGMP groups and Mroutes.

from the datasheets

Scalability Numbers

MAC, routing, security, and QoS scalability numbers depend on the type template used in the switch. Routing template is not supported in the LAN Base feature set. Table 10 shows Cisco Catalyst 3750-X and 3560-X Series Switch scalability numbers.

Table 10. Cisco Catalyst 3750-X and 3560-X Series Switch Scalability Numbers

	Access	Default	Routing	VLAN
Unicast MAC addresses	4K	6K	3K	12K
IGMP groups and multicast routes	1K	1K	1K	1K
Unicast routes	6K	8K	11K	0
Directly connected hosts	4K	6K	3K	0
Indirect routes	2K	2K	8K	0
Policy-based routing ACEs	0.5K	0	0.5K	0
QoS classification ACEs	0.5K	0.5K	0.5K	0.5K
Security ACEs	2K	1K	1K	1K
VLANs	1K	1K	1K	1K

http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps6406/data_sheet_c78-584733.html

4948

Table 1. Cisco Catalyst 4900 Series Features

Feature	Cisco Catalyst 4948 Switch	Cisco Catalyst 4948 10 Gigabit Ethernet Switch	Cisco Catalyst 4948E Switch
Performance
Switching capacity	96 Gbps	136 Gbps	176 Gbps
Throughput	72 million packets per second (mpps)	102 mpps	131-mpps IPv4 switching 110-mpps IPv6 switching
CPU	266 MHz	666 MHz	1.0 GHz
Synchronous Dynamic RAM (SDRAM)	256 MB	256 MB	1024 MB
Active VLANs	4096	4096	4096
Multicast entries	• 28,000 (Layer 3) • 16,000 (Layer 2)	• 28,000 (Layer 3) • 16,000 (Layer 2)	• 32,000 (IPv4 Layer 3) • 16,000 (IPv6 Layer 3) • 32,000 (Layer 2)

http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps6021/ps10947/product_bulletin_c25-600212.html

I hope that will help narrow down your decision.

Regards,

Dale

[Leo Laohoo]

Two 3750X-48T switches with stackwise cables connecting them together.

I would recommend you reconsider the choice of using 3750X-48T.  Look at the 3850-48T.  The price of the 3850-48T is the same as the 3750X-48T.