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Aaron’s blog on Networking, and Enterprise Technology

3750-metro frustrations. Worth it??

I am incredibly frustrated, and I’m hoping this post will save countless others from yelling out loud, after finding out you wasted money and hours of troubleshooting for no reason.

First off, a bit of history. Back in my historical posts, I mentioned my thoughts on the 3750-metro series switches. At first, I wasn’t all that impressed with the metro-series. I mean, it seems to be more for the service provider than for the customer. But, if Cisco recommends it for a customer, I should listen, right?

Well, Cisco sales reps are more interested in selling products, than in giving the best answers, and this is a perfect example. So, make sure to listen up, and pay attention.

In building our metro network, we have a fiber line, provided by AT&T. On the customer side, AT&T installed a Cisco switch to terminate the fiber, and hand-off copper. I then, take the copper into my network. But, after connecting my 3750-metro interface (The ES port, for “Enhanced Services”), I never saw a link. Hmmm… did AT&T enable their interface? I asked…. yep. Do I need a cross-over, or did they build the cross-over in their patchpanel? Nope. Straight-through. So, I must provide the cross-over
(And for those that will ask… no I do not trust the auto-sensing MDIX).

Still no luck.

Then, I asked AT&T the interface characteristics: (100Mbit – Full Duplex). Hmmmm…. shouldn’t be a problem. I’ll set my interface to that. What?? I can’t. It only accepts 1000? Let’s look at the docs:


Now, I consider myself a respectful and considerate human being (at times). However, I must say, when I realized that, I was glad I was in an isolated room with no one around. Because I yelled and cussed as I used to when I was a sailor in the Navy. At this point, I realized I have spent between $6k to $8k more than I needed to (I bought 2 metro switches, one for each side of the link), and I just wasted 3 to 4 hours of troubleshooting. I should have gone with my initial feelings about the 3750-metro.

So, what is the difference between the 3750 and the 3750-metro? From Cisco’s website:

Q. What is the difference between the Cisco Catalyst 3750 Metro Series and the Cisco Catalyst 3750 Series?

A. The Cisco Catalyst 3750 Metro Series is built for Metro Ethernet access in a customer location, enabling the delivery of more differentiated Metro Ethernet services. These switches feature bidirectional hierarchical QoS and Traffic Shaping, intelligent 802.1Q tunneling with class-of-service (CoS)
mutation, VLAN translation, MPLS, EoMPLS, and Hierarchical Virtual Private LAN Service (H-VPLS) support, and redundant AC or DC power. They are ideal for service providers seeking to deliver profitable business services, such as Layer 2, Layer 3, and MPLS VPNs, in a variety of bandwidths and with different SLAs. With flexible software options, the Cisco Catalyst 3750 Metro Series offers a cost-effective path for meeting current and future service requirements from service providers.

And what is this “ES Port” thing. What does it do for me?

Q. What are the Enhanced Services (ES) ports?

A. The Cisco Catalyst 3750 Metro Series includes two SFP-based ES ports. The ES ports support Metro Ethernet features that are vital for delivering profitable business services, such as Layers 2 and 3 and MPLS VPNs, in several bandwidths and with different SLAs. Supported features on the ES ports
include EoMPLS, MPLS, MPLS VPNs, bidirectional hierarchical QoS, intelligent 802.1Q tunneling (Q-in-Q) with CoS mutation, and VLAN ID translation.

So, to summarize, pretty much every enhancement the metro-line offers, is in the ES ports. Other than the redundant power-supplies, this is a wash. The regular Cisco 3750 still has a powerful QoS engine, and the same IOS commands. Now, I’m sure there is more in the metro software image than the standard 3750, but without the ES Ports, what’s the point??? The provider will provide the Q-in-Q tunneling, the heirarchical QoS, etc. What good does it do??

I’m still a little bitter, but by the time you post your comments, maybe I’ll feel better, and listen more. So feel free to let me know what you think. Right now, I’m disappointed, and frankly, quite pi$$ed, because I feel like I was taken advantage of.

My only advice is…. if you get the Cisco 3750-metro, please make sure the provider will hand off a 1000 Gigabit connection. Otherwise, you are sitting on an expensive 3750.

The only thing I can think of, is to place a media-converter in the middle, so I can use the 100Mbit ES interface. But, that just adds another point-of-failure, and this metro network was supposed to alleviate the failures… not add to them…..


16 responses to “3750-metro frustrations. Worth it??

  1. Aaron Paxson January 26, 2008 at 6:34 pm

    Okay, I had a small typo in my post. Did anyone catch it? It’s not a 1000 Gigbabit interface, but rather, just a Gigabit interface (or 1000 Mb). How cool would that be??

    So, I’m leaving a comment here, rather that a direct edit, to see if anyone caught it.

    Sneaky, huh?

  2. mzi January 30, 2008 at 5:03 am

    Hi !
    ES port will give you full MPLS when facing MPLS core, and you can do VPLS and xconnect on SVI. Things you can’t do with normal metro. If you are not using MPLS or you don’t need vlan translation, it’s useless for you.

  3. Raybones February 3, 2008 at 7:53 pm

    Hi Aaron,

    Did you find a solution to your problem? (other than the media-converter solution)
    It’s really the small part of unpredictable thing that can happen on a project like that…


  4. idiot April 25, 2008 at 1:16 am

    Isnt this simply a case of you not researching before purchasing? the ME3750 is designed for SPs to use as a CPE device in metro networks. It simply pushes the PE out to the customer site to provide some pretty cool functionality.

  5. Aaron Paxson April 25, 2008 at 6:13 am


    Yeah, just a simple case of not researching. Of course, there was no way of knowing what speed AT&T was to install, since they were sub-contracted out from Expedient. So now, my research has included Cisco’s product, Expedient, and Expedient’s Partners, to make sure they all fit together.

    All because an interface was set to 100-Full, instead of 1000-Full.

    Of course, if I were to do my own researching, Cisco wouldn’t need to spend millions of dollars on the Sales Reps and Resellers. Not to mention, all the time wasted on my end of not working, as I read hundreds of pages of technical manuals, learning the ins-and-outs of the each new product.

    Cisco will save millions! We don’t need Sales Reps. Let’s just do the research ourselves!!

    I feel like those Guiness paper cut-out dolls. Brilliant!

    And before anyone questions the way it was handled… at the bottom of the metro-3750 quote from my solutions provider, was an installation charge for my provider to install it.

    So, had I chosen to spend the money and had the provider install it, they would have ran into the EXACT same problem.

    (( grin ))

    • steveo February 9, 2010 at 5:01 pm

      ” AT&T installed a Cisco switch to terminate the fiber, and hand-off copper”
      That is the role the 3750 Metro is to fill.
      “provider install it, they would have ran into the EXACT same problem” No, I think you will find that had they installed it they would not have used their own Cisco switch. Their fiber handoff is gig so there would not be a mismatch.
      You got some bad advice from someone. Either that or poor project coordination.

  6. Richard October 29, 2008 at 2:52 pm


    I am researching the exact same issue with my 3750-ME’s – the inability of the IOS software on the switch to permit the “ES” (Enhanced Services) ports to support copper SFP’s at anything other then 1000-Full.

    If I can’t use the “ES” ports for my copper hand-offs from AT&T, then I can’t apply the necessary traffic shaping.


  7. cw November 1, 2008 at 7:00 pm


    you “should” be able to use the srr traffic shaping features on a standard port

    eg “srr-queue bandwidth shape 10 100 50 50” which should assign (and not to exceed) 1/10th, 1/100th, 1/50th and 1/50th of line speed to each of the four queues (respectively). I have not yet validated this in the real world but I am about to do so…


  8. yo August 17, 2009 at 12:10 pm

    Configure the ES port speed as nonegotiate

  9. Oscar Niemi September 25, 2009 at 6:03 am

    Why not just loop/connect a GE and ES port. Then you can get the ES functions on a FE port.


  10. Paul September 25, 2009 at 6:40 am

    one more ‘feature’ with the 3750m series is that you cannot stack them. they have the stackwise ports for stacking them using the stacking cables, but the ios for the metro series does not support this. basically it’s cisco’s way of keeping service providers on the 6500 platform and making more money.

    gotta love cisco.


  11. cisco sfp March 31, 2010 at 1:34 am

    Thank you for making the people aware of the difference between Cisco Catalyst 3750 Metro Series and the Cisco Catalyst 3750 Series, even i was in a confusion about which one should i go for, buit your post clarified my doubt.

  12. Richie December 14, 2010 at 6:11 pm

    This is an interesting post and it applies to my configuration. I already have a Cisco 3750 (model: WS-C3750G-12S) which I am planning to upgrade to the Advanced IP Services IOS to support the MPLS commands. We are getting a 10MB copper from the AT&T’s fiber that terminates into their own Cisco router. I called Cisco, but their Sales Rep was useless…could you guys let me know whether this configuration (with the switch I already have) would work for me? I am asking because all the posts I read about the 3750 being configured for MPLS mention the Metro ME model which I don’t have. Thanks for the help.

  13. Carlo January 20, 2011 at 3:31 pm

    I believe that the Metro series switches and the features
    provided on the ES port are worth it. The main advantage is if you
    are subscribing to sub physical rate EVCs. The heirarchical QOS
    gets you the ability to shape your outbound traffic to the
    subscribers rate, i.e. paying for 200Mb/s on a 1000Mb/s circuit. If
    you don’t shape your outbound, you are subjecting yourself to
    policing within the AT&T (or other) network and your TCP
    throughput drops to about 50% of the subscribed rate. You won’t be
    getting the throughput you are paying for. In addition,
    AT&T will drop traffic indescriminately. Voice and Video
    traffic will be as susceptible to drops as data traffic. Not Good.
    Yes, you will need to pay extra for a Gig handoff for 100Mb/s or
    less speeds. But at the 100Mb/s or less speeds, the advantage of
    the metro switch is less due to the ability of the ISR2 routers to
    provide 150Mb/s of throughput for a reasonable price. At 200Mb/s or
    greater, you are looking at 7200 with a NPE-G2 or an ASR1000 series
    router to gain the same QOS functionality at considerably higher
    price. Adding a Metro switch and a router in series for your Metro
    Ethernet allows you to do some interesting things also. 1. You can
    scale your throughput very high by offloading the QOS shaping to
    the metro switch and still have significant features of the router
    applied. or 2. get into some interesting oversubscription scenarios
    by using QOS shaping and CBWFQ on both the router and metro switch
    at the same time. This last topic is a bit deep to go over here but
    I can certainly explain it to any interested parties that reply…
    Another good application of the metro switch is to terminate your
    Opt-E-Man while breaking VLANs out for other applications. In
    AT&T, an Opt-E-Man can carry metro traffic, Internet
    traffic, and AVPN MPLS ports on separate VLAN IDs. This means you
    can trunk on your Opt-E-Man and use one of your Fast Ethernet or
    Gig Ethernet ports to connect to your Internet router and another
    for your MPLS WAN router and see a significant savings on your
    access charges vs dedicated Layer 1 connectivity for each. The
    metro switch wouldn’t be a Layer 3 hop for any of these services so
    no security risk is introduced. Of course you can do this with any
    switch but you will probably need to shape each VLAN individually
    depending on the bandwidth subscribed to for each service and
    that’s where the metro switch excels in a customer network. If you
    read all this then you are as crazy as I am!

  14. Janno July 25, 2011 at 2:46 pm

    Just RTFM, I had no problems with it from the beginning. It was all written down very well, even at the introduction some years ago. BTW 3600X/3800X also have limitations, but much less :-).

    • Aaron Paxson July 25, 2011 at 4:02 pm

      Thanks for the comment. You do realize this was posted almost 4 years ago? I’m sure docs and discussions have changed since then. I’m not sure you understood the context of the post. It was not about how the 3750-metro performs or is configured. Rather, it should have never been recommended to a customer in the first place.

      I agree with you, and admit, I should have done my homework rather than take a salespersons word on it. It’s not worth it for a CPE device. Rather, it’s for a provider.

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