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Beginner

887W jumbo frame?

Hi, I would like to know how to get 4088 byte jumbo frame support on the four LAN 10/100 ports. This is a ADLS2+ unit, so it would need to have MTU 1500 on the WAN port.

Any help greatly appreciated.

regards, Mark

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Hi Mark,

When you're switching through the 887 with non-jumbo frame setup are you changing the mtu on your end devices back to 1500 (or disabling jumbo frame support)?  If they're still sending jumbo frames the 887 could either be dropping them or fragmenting them, resulting in your slow speed.  The 887 should be able to switch 10-12MB/s on the lan ports.  If it's not I would suggest that there is something wrong elsewhere in your setup as only 25MB/s on a gigabit switch with jumbo frames is quite slow as well. 

Just to reiterate and confirm what others have already said - it's almost universal that fast ethernet (100Mb) connections do not support jumbo frames, so the 887 is not cutting corners here as you seem to suggest.  The 887 is meant to be an edge device, basically routing stuff over a dsl connection, and one normally doesn't require this type of device to switch at gigabit ethernet speeds.  If you really need gigabit switching, just use a gigabit switch.  This isn't a cheap and nasty router and if you dig into what ios is capable of you'll find that it goes far, far beyond what cheap home routers with built-in gigabit switches can do.  Yes, some cheap routers might indeed route faster, but without many of the features.  It's analogous to complaining that an expensive tractor can't go as fast as a cheap car on the road.  Different classes of devices.

Just out of curiosity, why exactly do you need jumbo frame support?  I use gigabit at home and at work, and the only place I've enabled jumbo frames is in a link at work between some servers and some storage devices for long backup transfers (many terabytes).  Between fast computers without jumbo frame I get ~60MB/s transfer speeds and I'm pretty sure disk speed is the limiting factor here.  Jumbo frame support wouldn't make much difference in this situation except with a very fast disk array.

Here's a cisco small business router which I think has the specs you're looking for (netgear makes some similar type/price routers also): http://www.cisco.com/en/US/prod/collateral/routers/ps9923/ps9931/data_sheet_c78-496737.html

Not sure about jumbo frame support, but seriously, I wouldn't worry about it.  If you're only getting 25MB/s then you're not benefiting from it and you have other issues to sort out first.

Regards,
Eric

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29 REPLIES 29
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Hall of Fame Master

Generally speaking, Cisco 10/100 ports do not support jumbo frames.

That is not a problem espcially in you application that would not benefit from them,

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oh please - I can't believe this would be true - surely not?

Not only is the brand new 887W a shocker by having four 10/100 ports when it would probably have cost $10 more for the 1000 Mbps chip. The 802.11n must be hamstrung as well, as it should do 300 Mbps, but can't connect to anything on the LAN at that speed. And now I learn that the four port 10/100 Mbps switch can't do Jumbo frames?

Nah - can't be - someone from Cisco please tell me this is not so?

Remember Wang, DEC, Sun, and the long line of other companies that started to overcharge for poor products that they tried to sell as the latest and greatest and then went broke? Well I'm expecting to add Cisco to the list soon.

Cisco should put out new 800 series devices that have basic features (jumbo frames, four port 1000 Mbps switch, real 802.11n) and then provide upgrades using a free return policy (I'll happily pay the freight).

I'm really hoping someone will tell me that I'm wrong and jumbo frames can be supported on the 10/100 Mbps ports - as this is required to ensure a LAN can operate at a reasonable speed today.

And yes, your right, I appear to be a real blockhead by buying a 887W

regards, Mark

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I'm really hoping someone will tell me that I'm wrong and jumbo frames can be supported on the 10/100 Mbps ports - as this is required to ensure a LAN can operate at a reasonable speed today.

Yes you are wrong on the matter that jumbo frames "ensure reasonable speed" - they do not, especially at 100 mbps, as any networking professional could tell you.

You are then of course entitled to return the product if dissadisfied, and/or believe whatever you want on the matter above.

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Mark-

I'm sorry to hear that the router that was suggested to you for purchase did not have the features you require. The 800 series is an entry level router and the typical location that this router would support would not need to support 10/100/1000, jumbo frames, etc. If your network needs jumbo frames, then you will not want that traffic to go through an 800 series router. Take a look at a stand-alone switch, you'll get the features you need. If you would like help figuring out what router/switch you need, post your requirements and we'll try and help. A reputable Cisco partner can also be a great resource for correct product selection.

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Hi,

I purchased the 887W about one month ago, without realising it was so limited. Given the price and the recent release of this device I thought it was "up to date".

My requirements are:

ADSL2+

Capability to have ACL and translation for multiple extrernal IP - I have one public IP on the external interface and a 3 bit subnet of 8 public IP

802.11N v2 (up to the full speed of 300mbps)

LAN four port 1000 Mbps switch

LAN support for jumbo frames to 9000 bytes

VPN from WAN to LAN

I don't think I have missed anything.

regards, Mark

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mgregory@agama.com.au

Hi,

I purchased the 887W about one month ago, without realising it was so limited. Given the price and the recent release of this device I thought it was "up to date".

My requirements are:

ADSL2+

Capability to have ACL and translation for multiple extrernal IP - I have one public IP on the external interface and a 3 bit subnet of 8 public IP

802.11N v2 (up to the full speed of 300mbps)

LAN four port 1000 Mbps switch

LAN support for jumbo frames to 9000 bytes

VPN from WAN to LAN

I don't think I have missed anything.

regards, Mark


Mark

If you really need gigabit ports then you need a switch simply because even though many routers come with gigabit interfaces they can't support that amount of throughput. Similarly you say your 802.11n is hamstrung but again the 887 will nowhere near support that amount of throughput. To give you a realistic idea if you wanted throughput greater than 100Mbps on a router then you would need a 2851 at least. Note the 2900 routers support greater throughput but i don't have figures for those.

But you don't buy routers for LAN performance. If you need LAN performance then buy L2/L3 switches and wireless APs to connect to these switches.

The 887 could still be used for ADSL connectivity/VPN and acl/NAT.

So you need to be realistic. If you truly need the sort of throughput you are talking about it is going to cost a lot more than an 887 router. A lot depends on your real bandwidth requirements/needs vs the budget you have.

The switch could be L2 if you only have or need one vlan in your LAN and it's default-gateway could be the 887 but if you need multiple vlans now or in the forseeable i would recommend at least a L3 switch.

Wireless is not my speciality so you may want to post in the WLAN forums but you would be looking to connect this to the internal switch.

Jon

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Hi,

I don't agree with your reply. A processor capable of switching a 4 port gigbit lan and 802.11n wireless is not a magical thing, it is inexpensive and such processors with this capacity were available many years ago.

On the whole I have learnt the 887W has 802.11n so that it can be sold as 802.11n capable and then everything below that appears to be no different to the 837 that I'm upgrading from.

I don't want to have a separate switch and a separate access point - I bought the 887W thinking I could turn all of the other devices off and save power.

Your suggestion of a 2800 series device would, and I'm guessing here, cost about $3000-$5000 for what should be a sub $1000 device.

Why I'm upset is that in my old setup I had all of my systems connected to a 24 port HP procurve gigabit switch which was connected to a PIX 506E then the 837 and finally the ADSL. So many devices wasting electricity (which is nearly 50% more expensive this year). I had a 802.11n access point connected to the 24 port HP procurve gigabit switch.

I could run jumbo frames on my network without difficulty. And yes this is important as I had speeds of about 25 Mbps around my network. Having put the 887W in place of the 837 and turned the PIX 506E off, I find that my jumbo packets are being dropped by the 887W and I have had to go back to mtu 1500 and my network speed is back to around 1-2 Mbps (what a backward step).

I would appreciate knowing of a device, the configuration (NIC cards) and anticipated cost of what I need. If possible, I need to keep the cost to a reasonable level.

regards, Mark

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Mark

I don't agree with your reply.

A processor capable of switching a 4 port gigbit lan and 802.11n wireless is not a magical thing, it is inexpensive and such processors with this capacity were available many years ago.

I never suggested it was "magical", i was simply trying to point out that the Cisco 887 doesn't do that. Now if you want to write to Cisco and point out their obvious mistake based on your knowledge of processors then fine but that still won't make the 887 do what you want. I'm not trying to be difficult but simply stating these processors have been available for years does not really have much relevance.

Your suggestion of a 2800 series device would, and I'm guessing here, cost about $3000-$5000 for what should be a sub $1000 device

please re-read that bit. I wasn't suggesting you purchase one i was simply using it as an example. However what makes you think it should be sub $1000 ?

Why I'm upset is that in my old setup I had all of my systems connected to a 24 port HP procurve gigabit switch which was connected to a PIX 506E then the 837 and finally the ADSL. So many devices wasting electricity (which is nearly 50% more expensive this year). I had a 802.11n access point connected to the 24 port HP procurve gigabit switch.

So basically you had pretty much the setup i suggested and you thought somehow an 887 could replace all that ?  Unless you go for a high end router, and believe me they are expensive, if you want gigabit connectivity you need a switch.

I try to be as helpful as possible when replying in threads but i see little point in suggesting any device(s) as you will probably tell me you don't agree again with what i am saying

Jon

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Beginner

Hi Jon,

I'm interested in suggestions for a suitable device. If it is a reasonable suggestion, then I would have no reason to object.

It must be obvious why I need a solution - I'm upgrading from ADSL to ADSL2+ and the 837 will only do ADSL.

So, please if you have a device in mind and can tell me of any NIC or other costs, I would be very pleased to learn of it. I'm interested in knowing what is available, irrespective of cost, then I will need to evaluate if I can afford to replace the 887W. Unfortunately, I don't think I will be able to return the 887W as this is not normal in Australia - so it can be used as a brick.

regards,

Mark

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mgregory@agama.com.au

Hi Jon,

I'm interested in suggestions for a suitable device. If it is a reasonable suggestion, then I would have no reason to object.

It must be obvious why I need a solution - I'm upgrading from ADSL to ADSL2+ and the 837 will only do ADSL.

So, please if you have a device in mind and can tell me of any NIC or other costs, I would be very pleased to learn of it. I'm interested in knowing what is available, irrespective of cost, then I will need to evaluate if I can afford to replace the 887W. Unfortunately, I don't think I will be able to return the 887W as this is not normal in Australia - so it can be used as a brick.

regards,

Mark

Mark

If you try to do this with one device it will cost you a fortune. I cannot stress enough that routers that support gigabit throughput with enough gigabit ports would be the high end routers only and they really are expensive. That is why switches are used in the LAN because you get much better throughput for much lower cost.

What you had with your original setup in terms of HP procurve with an AP connected to procurve is the best solution. You simply change the 837 with the 887. The 887 will happily do WAN/VPN + acls/nat. So it's not that the 887 is a bad choice, it's just that it will only replace the 837 and not all the devices.

Jon

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Hi Jon,

I still have the procurve switch and it is connected to one port on the 887W.

I bought the 887W because it includes 802.11n v2 - therefore it is reasonable that it will operate at max speed and talk to other devices at a reasonable speed. I boggle that it runs at 300Mbps and can only talk to devices on the network, such as my media NAS at 100 Mbps

I bought notebooks that have 802.11n for this very reason.

I don't see why a single device would not do what I want. The 887W needs a $10 chip upgrade on the LAN switch to 1000 Mbps and jumbo frames would follow. If necessary the 887W may need a $20 processor upgrade to have greater capacity.

Anyway, I'm very happy to recieve device recommendations.

regards

Mark

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Mark

I bought the 887W because it includes 802.11n v2 - therefore it is reasonable that it will operate at max speed and talk to other devices at a reasonable speed. I boggle that it runs at 300Mbps and can only talk to devices on the network, such as my media NAS at 100 Mbps

are you actually getting anywhere near 100Mbps ?

Jon

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Mark

I actually overlooked the ISRG2 routers which actually have switch modules that are based on Cisco switches. So these may be a possibility. Still won't get to 1Gbps through the router but it would give gigabit on the switch itself. The ISR G2 routers are 1900/2900/3900 series devices. You may want to look at the product pages for them and then come back if you have further questions -

http://www.cisco.com/en/US/products/hw/routers/index.html

So go to "Branch routers"  and select router and then for each router series there will be a datasheet and relevant modules you can use. This still won;t be that cheap though compared to simply deploying the 877 in place of the 837.

Jon

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Hi Jon,

as I mentioned with jumbo frames set on all devices I get up to 25 Mbytes per second around my network. Now I'm back to the 1-2 Mbytes per second that is possible when frames are set to mtu 1500

I could not recommend any solution today that does not include support for 4088 byte or 9016 byte jumbo frames.

Yet, I have been silly enough to purchase the 887W without noticing the lan ports were 10/100 - I just could not imagine a company selling 10/100 today and this is my excuse for not noticing - and yeah I'm shocked now as I believe the 887W to be a really poor product that seems to be a marketing exercise.

regards,

Mark