3750G-24TS or 3750E-24TD?

[hxmengmetro]

Hi All,

I'm considering to get two 3750 switches stacked as our distribution switch. I'm still doing L3 to the core and L2 to the access switches. I don't have to put enhanced image on 3750 switch since we can use EIGRP stub on IP base image for the distribution switch. The only advantage 3650E has is the wire speed performance. 2x10GE uplinks could benefit the future upgrade. Since I'm seeing lots of discarded packets in our current 3560G switch. I'm thinking the upgrade to 3750E could solve the discarded packets issue caused by bursty traffic. How do you guys think? Any advantage from 3750E? In addition, IP base image should be enought, right? I don't have any routes from the distribution switch to anywhere else. Only to the core routers.

Thanks a lot.

Lou

[Reza Sharifi]

Hi Lue,

With IP base image, you can run EIGRP Stub, RIP and static route. So, if EIGRP Stub is all you need, you should be fine.  As for 3750E, you can probably purchase 3750X for the same price since theses are the newer series.  It also gives you a couple of advantages over 3750E, 1-Use 10Gig or 1Gig without using a Twin Gig converter 2-Redundant fans and power supplies and 3-The option to stack power supplies between multiple switches (up to 3).

HTH

Reza

[hxmengmetro]

Thanks a lot Reza. What model are you using? As for the backplane performance, do you see much difference in the real world regarding to 3750G and 3750E/X?

Lou

[Reza Sharifi]

The Switch fabric capacity for the E and X is the same.  They are both 160Gig. The 3750G is only about 32Gig.

I have only tested the X series.  They are pretty nice boxes.  I like the power redundancy and stacking. I think, it can be useful for POE devices.

HTH

Reza

[Leo Laohoo]

Nice post Reza (+5).

Have you tested the booting the "X" using USB?

Try it!  Also, put the switch into ROMmon and the USB option works too!  Wicked!

[Reza Sharifi]

Leo,

Thanks for the rating my friend!!!

I have never tested the USB. I will try these options.

I always thought, the USB ports on the smaller routers and switches are useless just like the once that come with Sup-720-VS.

Thanks,

Reza

[Leo Laohoo]

I always thought, the USB ports on the smaller routers and switches are useless just like the once that come with Sup-720-VS.

Hey Reza,

Don't get me started with topics like "USB" and "Sup32/Sup720" in the same sentence.   Grrrr ...

On the bright side, the soon-to-be-released VS-Sup2T will support USB drives (I'm suspecting 8Gb won't be an issue).  The WiSM-2 and new 6500E modules will also support USB but not for booting purposes.

We've been testing USB boot (both normal and ROMmon) on the ISR G1 (except the 870), G2, 3750X and the 2960S. 

[Reza Sharifi]

Hi Leo,

Can I use any off-the-shelf  USB flash card or it has to be a specifics brand/size. I heard that not every USB brand works with Cisco devices.

Also, need to be 2.0 version?

Thanks!!

Reza

[Leo Laohoo]

Can I use any off-the-shelf  USB flash card or it has to be a specifics brand/size.

Firstly, not all USB flash drives are supported.  I believe some are manufactured using non-standard means.  I have one that I tested on a 2960S and the switch went ape!  I mean it would constantly crash, boot, crash, boot, non-stop.  All I did is boot the 2960S normally, plug the USB stick and VIOLA!

For the ISR G1 (except the 870) I tested all the way up to 2Gb.  Some have claimed to use up to 4Gb but I did not have the opportunity to try.

Also, need to be 2.0 version?

Haven't heard of this before.

[hxmengmetro]

Reza,

I simply tested the redundancy last week. I have two ip phones connected to the core from different distribution switch. When I powered down the master 3750, there was a several seconds silence over the conversation. I didn't hear my coworker's voice and he didn't hear mine either. Is this normal for stacked 3750 or is there anything I can tweak to make it better? Since the VoIP is UDP, lost is lost. No way to make them retransmit. I guess the only way to make it better is to shorten the down time when the master switch goes down.

Thanks for your help.

Lou

[bill.greenwood]

Discarded packets are due to congestion, there are more packets than buffers to send the traffic out the interface. You should look at adding capacity to the link where you are seeing the discards. Without knowing the environment I would suggest creating a etherchannel between your switches or added to existing an existing etherchannel before spending the money on new switches.

Bill

Sent from Cisco Technical Support iPhone App

[hxmengmetro]

Hi Bill,

Thanks for the recommendation. I'm planning to do that too. But since we only have one 3560G distribution switch at this time, we decide to buy another one or two switches for redundancy. If we use two stacked 3750, each access switch will have 2G links to the 3750s. The reason I don't use another 3560G for the redundancy is I don't want to deal with STP and leave another link from access switch to do nothing.

I will add more links for some access switches to check whether the discarded packets will be gone or not.

Thanks.

Lou

[iskoy.istem]

I have read these switches data sheets (3750G, 3750E and 3750X). 3kX series of Cisco seems to be designed down to access or distribution only. i have compared its unicast mac-address entries, classic and E-series has 12,000 configurable unicast mac-address but 3750X only has 4k.

[hobbe]

Hi

I think you mean this table

it is taken from the link

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

Table 7. 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

actually this is the same table for both 3750E and 3750X (I think all the way down to atleast 3750 v2)

So what is this ?

This is a switch memory configuration table.

You can configure how the switch uses its memory for what you need.

if you are not using the swith for L3 then you can configure it for VLAN and get 12K unicast MAC addresses but you can not do routing since there is no memory for that. on the other hand if you are using the switches for routing purposes you can set it to routing and you will have 8K indirect routes but the drawback is that you will "only" have 3K unicast MAC addresses.

how to configure this.

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750x_3560x/software/release/12.2_55_se/configuration/guide/swsdm.html

And to answer the original question

I would go with the 3750X instead of the 3750G or E and I would actually not connect the 3750G since that will slow down the stack.

good luck

hth

[hxmengmetro]

Thanks!!