I am really confused with this, kindly guide me
What advantage do i get with connecting nexus 2k with nexus 5k when i can connect 2960x with 5k also ? i mean i see certain disadvantages of nexus 2k like
1) expensive then 2960x
2) dumb terminal, even for local traffic, it has to send to parent switch
3) has 24 1G ports and 2 10g ports just like 2960x 24TD model
I can easily use 2960x as top of row switches, and a whole bunch of advantages also.
What you guys think i might loose if i prefer 2960x over FEX ?
Solved! Go to Solution.
I'm not sure I would accept the cost argument. If you are a partner, you or your pre-sales staff can build priced configurations to compare them. For the sake of argument, and ccomparing purely on a cost basis, below are a couple of sample configurations based on list pricing.
I would also note that often the initial discussion about "oh sell us this model because it's __% less it's OK" is oftern forgotten when the customer starts putting production data traffic through the gear and it fails to match expectations (even when those expectations are unrealistic given the pre-sales warnings). Whether you are the vendor (Cisco) or a partner, you have a responsibility to strongly recommend solutions that support the customer's needs to the best of your ability.
As Reza mentions, 5k bundles are oten offered (special deals may be available for 2960X as well but may not be qualified deals if you are building a non-recommended solution):
WS-C2960X-48TD-L (Catalyst 2960-X 48 GigE, 2 x 10G SFP+, LAN Base)
Catalyst (2960-X FlexStack Plus Stacking Module) (optional)
If you want dual power supplies on a 2960X you need to move up to the XR series, at higher cost still:
Catalyst 2960-XR 48 GigE, 2 x 10G SFP+, IP Lite
250W AC Config 2 Power Supply
Catalyst (2960-X FlexStack Plus Stacking Module) (optional)
That is all as contrasted with the Nexus 2k option (already including two power supplies standard and 4 x 10 Gbps uplinks vs. 2 maximum in the 2960X)
N2K GE, 2 AC PS, 1 Fan (Std Air) , 48x100/1000-T+4x10GE
No stacking modules required, dual power supplies already included.
One difference between using 2k vs 2960 is management. When you connect let say 20 2k switches to a pair of 5ks, you only manage the 2 5ks, because all the 2ks connecting to the 5ks appear as ports and not separate switches. In the case of 2960, they are all separate switches and not managed by the 5ks. Think of it this way, you have a 6509 switch fully loaded for a total of 7 blades and 2 sups. Now, think of each blade not being in the Chassis, but being installed as top of the rack switches. So, one blade is installed in rack-1 and another installed in rack-2 and so on. But you know you cannot do this with 6500 because the blades have to be inside the chassis. But this is easily possible when using 5ks as parent switches and 2ks as blades or ports.
2960X vs. Nexus 2k is a very different proposition. The 2960 is not a data center class device and has limits on functionality.
For instance, in a data center you typically want to have end to end high availability. If a given server has multiple NICs, you don't want it to depend on a single upstream device. With a Nexus solution you can run server to 2k to 5k all with multiple connections using enhanced VPC and have seamless failover in the event of failure as well as true non-blocking throughput.
Also when you start pushing significant amounts of data across multiple ports simultaneously, the 2960X would run out of buffers and other such resources long before a 5k with 2k FEX would. This is especially important if you are connecting storage (FCoE etc.) directly to your top of rack switches.
There are also more options in FEX types, including 10 Gbps ports that are not available at near the scale in any Catalyst 2k or 3k product.
By the way one limitation on the Nexus solution is that a 5k (or pair of 5ks) can currently only have up to 12 FEXes associated.
Sir, just for the sake of discussion,
2960 backplane throughput is more then nexus 2k (thats what i saw in datasheet). For a server with 2 nics, they can be connected to 2960 switch just like they can with Nexus 2k. And since 2960 will be connected via vPC to nexus 5k, i think there will be seamless failover right ?
Remember, 2ks don't have any backplane. They are just ports/blades of the 5ks or 6ks or 7ks. You can't even load OS on 2ks, when you upgrade the parent switches, they will push the OS to all 2ks.
And yes, the 2960s with work fine too, but as Marvin also noted, the 2960s are not designed for data centers.
Sir i just need clarifications on below remarks from Sir Marvin,
"For instance, in a data center you typically want to have end to end high availability. If a given server has multiple NICs, you don't want it to depend on a single upstream device. With a Nexus solution you can run server to 2k to 5k all with multiple connections using enhanced VPC and have seamless failover in the event of failure as well as true non-blocking throughput."
Can we do the same with 2960 ? 2960 can also have multiple connections to upstream Nexus 5k and providing all services that nexus 5k usually do with nexus 2k ?
"Also when you start pushing significant amounts of data across multiple ports simultaneously, the 2960X would run out of buffers and other such resources long before a 5k with 2k FEX would. This is especially important if you are connecting storage (FCoE etc.) directly to your top of rack switches."
Can i read more about it, like buffer limitation of 2960 vs Nexus 2k ?
(Sir i am asking all this because i will be facing a customer who is very keen on these concepts, thats why i just want to know some solid reason why 2960 is a bad choice vs Nexus 2k)
With Nexus 2k, the dual NIC server can connect to multiple FEXes. You cannot similarly form an multi-chassis Etherchannel with two 2960s.
Feel free to build your data center using Cat 2k's - Ethernet will work after all. Just be prepared to rip it out and replace with higher performance equipment if you ever start pushing significant traffic through it.
Remember - you should not be comparing 2960X vx 2k FEX directly - the 2k FEX gets most of its capability from the parent 5k. Even so, the 2960 has 2 or 4 MB buffer (Table 2 here). The FEX 2248 has 32 MB (Table 1 here).
Either 802.3ad or LACP link aggregation schemes depend on one device at each end to negotiate the aggregated port.
The Nexus can "fool" the end device into this using Virtual portchannel (VPC). The 2960X has no such capability; so a given aggregated server connection has to terminate in a single 2960.
Higher end Catalyst (4k and 6k series) can accomplish it using Virtual Switching System (VSS) and multi-chassis Etherchannel (MEC) technologies.
Absolutely excellent. Marvellous.
Sir this is what i have understood from your great explanation. Please vet the following points
1) Nexus 2k is simply an extension of Nexus 5k. Nexus 5k can run VPC, so that servers connecting to 2 FEX are infact being connected to nexus 5k so due to vpc they will think they are connecting to same switch.
2) 2960s are independent switches and dont support VSS or VPC, thus they cant fool the servers connecting to them to think they are 1 switch and cant benefit from vPC.
That's mostly correct - it's actually a pair of 5k's running VPC. A single 5k would run "plain" portchannel.
Please refer to the following for more detailed explanation of configuring (enhanced) VPC on the Nexus 5k: Reference Link.
Sir just 1 thing more. Lets say i have 2 2960s and a server with nic teaming to both these switches. If i stack 2960s switches together, which are further connected to nexus 5k, doesnt it make the same scenario ? i mean now servers are connected to 2 different switches but thinking they are connected to the same ?
Yes a stack is a single logical switch and you could run a portchannel with interfaces in multiple stack members.
As I pointed out earlier, many things CAN be done with the lower end switch. In a data center environment, that does not mean they SHOULD be done. The 2960X is an access switch for a reason and the Nexus 2k are data center server switches for a different set of reasons. There are thousands of engineering design and manufacturing hours that go into the respective software and hardware components to make each do best what it is designed for.
Think of the analogy of a car. Can a Toyota Corolla go at 150 kph? Yes. Can Mercedes S Class also go 150 kph? Yes. Do we want to travel 24-7 in the Corolla at that rate of speed? Are brakes designed to operate at high speed when needed? Will engine blow up sooner? If there is a crash which will protect occupants better at that speed?
Sir i totally agree with you, its just that, due to cutting expenses, clients ask these and sometimes prefer these scenarios. Due to budget contraints, they might wanna buy 2 nexus 5k with a bunch of 2960x series to start out with nexus world and perhaps later in future, migrate to FEX.
Sir if you can please tell me some reference documents that can help me better understand nexus 2k architecture with 5k then i will really appreciate. I have partner access just to let you know
Have a look at the data sheet for the 5500 and the 2000 series switches. The 2000 series switches are not very expensive.
Talk to your sales rep. You may be able to get a package deal with 5ks and 2ks and may end up being cheaper than using 2900 series.