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ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

Welcome to the Cisco Networking Professionals Ask the Expert conversation. This is an opportunity to discuss with Cisco experts Vipul Redey and Anupam Barua about the implementation of the new catalyst switches. Vipul Redey is a product manager at Cisco's Desktop Switching Business Unit. He has managed several Catalyst 3560 and Catalyst 2960 switching products. Anupam Barua is the product manager for Catalyst 3750 and 3750-E series switches. He is responsible for the overall life-cycle management of these switches including monthly forecasting, roadmap, product strategy, pricing, product launch and various other activities.

Remember to use the rating system to let Vipul and Anupam know if you have received an adequate response.

Vipul and Anupam might not be able to answer each question due to the volume expected during this event. Our moderators will post many of the unanswered questions in other discussion forums shortly after the event. This event lasts through April 20, 2007. Visit this forum often to view responses to your questions and the questions of other community members.

74 REPLIES
Community Member

Re: ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

Hi,

Could you tell me if BFD is on the E and non-E series roadmap? And if so, when it is likely to arrive in deployable code.

Thanks

Andy

Community Member

Re: ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

No BFD is not in the roadmap for this year. We may look into it next year and beyond - stay tuned.

Thanks,

-Anupam.

Re: ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

Our problem with the current Catalyst 3750 and 3560 switches is the limit on spanning-tree and HSRP instances. The Catalyst 3750 for example is limited to 128 STP instances and is similarly limited in terms of HSRP instances.

Is there any plan to support more STP and HSRP instances on these switches?

Silver

Re: ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

Hi,

Is there a support for Q-in-Q / EWS in 3750???? I hope it is there in 3550-E??

Rgs

Community Member

Re: ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

Yes, Q-in-Q support has been there in the 3750 for more than a year now. And the new 3750-E also supports Q-inQ.

-Anupam.

Community Member

Re: ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

The new 3750-E and 3560-E will still support 128 STP instances. You can easily get over this limit by implementing RSTP/MSTP - you'll get much faster convergence (usually in 2/3 sec) than the traditional STP.

As far as HSRP is concened, the new switches will still support 32 unique group numbers, however, the group number can be reused across VLANs, so if you reuse the group numbers, you can configure 32 groups in each of the 1000 VLANs. So theoretically, the switch can support 32000 HSRP groups.

Thanks,

-Anupam.

Community Member

Re: ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

"As far as HSRP is concened, the new switches will still support 32 unique group numbers, however, the group number can be reused across VLANs, so if you reuse the group numbers, you can configure 32 groups in each of the 1000 VLANs. So theoretically, the switch can support 32000 HSRP groups."

actually i didnt understand this how you can configure the HSRP for more than its limit group?

will you please provide some link to configure the HSRP as given in above explanation?

Community Member

Re: ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

Before there was a hard limit of 32 HSRP group numbers that can be configured in the 3750 or 3560 switches. Now the limit is still there but it is per VLAN, instead of per switch. You can have for example, Group 1 in all your VLANs, and Group 2 or Group 3 the same. So in theory, since the switch supports 1000 VLANs, you can configure (1000x32) = 32000 HSRP groups.

For details on HSRP cnfiguration, please refer to the following:

http://www.cisco.com/en/US/products/ps7077/products_configuration_guide_chapter09186a008077a293.html

Thanks,

-Anupam.

Re: ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

Hi Anupam,

Regarding re-using the same HSRP standby group in all VLANs, won't it create a problem since the virtual mac address will be the same?

Thanks,

Dandy

Community Member

Re: ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

Virtual MAC address will be associated with the Redundant Layer 3 Hops. Different VLANs can have the same default gateway - in this case they will just point to the same virtual MAC address - that's not a problem.

Thanks,

-Anupam.

Re: ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

Hi Anupam,

Thank you for your reply.

In my case, its different VLAN with different Default Gateway but the same standby group - woulkd that be okay? i.e.

SW1# show standby

Vlan101 - Group 1

State is Active

2 state changes, last state change 00:20:03

Virtual IP address is 192.168.160.1

Active virtual MAC address is 0000.0c07.ac01

Local virtual MAC address is 0000.0c07.ac01 (v1 default)

Hello time 5 sec, hold time 15 sec

Next hello sent in 3.641 secs

Authentication MD5, key-string "secret"

Preemption enabled

Active router is local

Standby router is 192.168.160.3, priority 70 (expires in 9.992 sec)

Priority 90 (configured 120)

Track interface FastEthernet1/0/1 state Down decrement 30

IP redundancy name is "hsrp-Vl101-1" (default)

Vlan102 - Group 1

State is Active

2 state changes, last state change 00:20:06

Virtual IP address is 192.168.161.49

Active virtual MAC address is 0000.0c07.ac01

Local virtual MAC address is 0000.0c07.ac01 (v1 default)

Hello time 5 sec, hold time 15 sec

Next hello sent in 0.236 secs

Authentication MD5, key-string "secret"

Preemption enabled

Active router is local

Standby router is 192.168.161.51, priority 70 (expires in 14.413 sec)

Priority 90 (configured 120)

Track interface FastEthernet1/0/2 state Down decrement 30

IP redundancy name is "hsrp-Vl102-1" (default)

SW1# show arp

Protocol Address Age (min) Hardware Addr Type Interface

Internet 192.168.161.52 0 Incomplete ARPA

Internet 192.168.161.49 - 0000.0c07.ac01 ARPA Vlan102

Internet 192.168.161.50 - 001b.2bde.1a43 ARPA Vlan102

Internet 192.168.160.1 - 0000.0c07.ac01 ARPA Vlan101

Internet 192.168.160.2 - 001b.2bde.1a42 ARPA Vlan101

Internet 127.0.20.20 - 0000.0000.0000 ARPA Virtual2

Dandy

Community Member

Re: ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

Yes this will work. In this case the virtual MAC address associated with two different IP addresses - points to the same physical switch. There shouldn't be any issues.

Thanks,

-Anupam.

Re: ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

Hi Anupam,

Thanks for confirmation.

I think the 32000 HSRP won't work in 3750 after creating 32 HSRP (all standby 1) in 32 vlans, I won't be able to apply anymore HSRP. Since the topic is 3750-E/3560-E, I think it will work only on these models.

Thanks,

Dandy

Community Member

Re: ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

You are right. This enhancement is only available in the 3750-E and 3560-E switches. 3750 and 3560 still have the limitation of 32 HSRP groups.

Thanks,

-Anupam.

Community Member

Re: ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

Hello,

When the master host in a stack fails, which services are reset/reconverged? I read that routing is flushed. How much downtime is expected after the master host fails? Also, when a switch is added/removed from the stack, is downtime experienced by other switches?

Thanks,

Lee

Community Member

Re: ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

When the master switch fails all the Centralized features will be affected, they include - routing protocols, HSRP, Multicast routing, CDP, CLI, telnet etc. Depending on your network design and the use of fail-over mechanisms - the downtime can be sub 1 sec to 5 seconds. In the 3750-E we also support NSF (non-stop forwarding) with the NSF configured, you'll probably have no downtime.

We support hot removal/insertion from the stack - so there shouldn't be any downtime experienced by other switches as long as first, you power down the switch in question, and then add/ remove it to/ from the stack.

Thanks,

-Anupam.

Community Member

Re: ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

Hello,

I've looked at the performace specs of the 3750E and I see that the forwarding rate of the 24 port is 65.5 Mpps, and the switching fabric is 128-Gbps. Does this mean that L3 traffic is routed at 65.5 Mpps and L2 traffic is switched at 128-Gbps?

Thanks,

Lee

Community Member

Re: ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

The performance is 65.5 Mpps for both L2 and L3 traffic. What this basically means is that the switch is wire/line rate.

Community Member

Re: ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

So is there no performance difference from a switch that is only performing L2 switching than a switch that is performing L3 routing? I've noticed that only L3 devices have references to Mpps, while L2 only devices have Gbps. Why is this?

Community Member

Re: ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

Where do you see that? Even for our L2 switches like 2960 series, we quote the performance in Mpps and backplane capacity in Gbps. Mpps refers to how many packets the switch can handle when all ports are runnig at line rate i.e 100% of the speed of the port. Gbps refers to backplane capacity of the switch - it is used to figure out if the switch is oversubscribed or not - for example, if you have a 24 port 10/100/1000 switch - then the backplane capacity of that switch has to be at least 24 Gbps for the switch to be line rate. Anything less than that - the switch will be termed oversubscribed.

Hope this helps.

Thanks,

-Anupam.

Community Member

Re: ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

Hi,

following a previous message, what does the forwarding rate 65.5 Mpps measure? How does this relate to bps? Is this rate supposed to be for 1 Gb ports?

Community Member

Re: ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

Mpps measures the number of packets the switch can handle when all ports of that swtich are running at line rate. We calculate that based on 64-Byte packet length. To translate this to bps - you first have to convert the Byte to bit.

-Anupam.

Community Member

Re: ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

Hi Anu,

We r in the process to setup a network running voice/video/data in this network. One of our consultant says at any given point of time the load on respective (user's) ports will not be more then 256K (let us issume 1Mb).here he is recommending C3560G with 10/100.(Access layer)

My questions is y not 10/100/1000 for this type of network, if not with this type of network then can u please let me know on which network we can use 10/100/1000.

Thanks,

Raj

Community Member

Re: ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

It all depends on the bandwidth requirements of the application. 10/100 may be sufficient, with 1/100/1000 you are future-proofing your network for applications that may require more bandwidth in days to come.

Thanks,

-Anupam.

Community Member

Re: ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

Hi,

Would you consider a 3560 a suitable distribution layer switch according to the three-layer hierarchical design? If so, woudn't you run netflow at this layer? Are there any plans to introduce netflow to this or similar model switches? as the core is supposed to be low latency - high speed isn't it against good design to enable netflow at the core on a highend switch?

Thanks in advance,

Andres

Community Member

Re: ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

We don't recommend putting 3560 in a distribution layer. You can probably use it in the distribution for a small size network with less than 50 users or so. Modular switches like 4K/6K are ideal for distribution. These swtiches also provide the performance and functionality required at the distribution layer.

There is no plan to support Netflow in 3560/ 3560-E or 3750/ 3750-E series switches due to hardware limitation - this is yet another reason to use modular switches at the distribution or core layer.

Netflow is implemented in hardware so in general there shouldn't be any performance impact for enabling this feature in the distribution/ core layer.

Thanks,

-Anupam.

Community Member

Re: ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

What routing differences there are with 3750-E and non-E catalyst?

Can you define vlan interfaces and route between them?

Community Member

Re: ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

There is no routing difference between the 3750-E and 3750 series Catalyst switches.

Yes you can configure VLAN interfaces and route between them.

Thanks,

-Anupam.

Community Member

Re: ASK THE EXPERT- NEW CATALYST 3750-E AND 3560-E SWITCHES

Can you give me some information on how the 3750E platform handles OSPF type 5 LSA's. I noticed in between the 3550's and the 3750E it sends the packet diffrently? More specificly the Default info originate in the packet.

Thanks,

Chris

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