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Recommendations with current networking setup

Discussion in 'Networking' started by stockhouse50, Oct 12, 2017.

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  1. stockhouse50

    stockhouse50 Thread Starter

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    Hi, I have taken over this setup and I could use some help understanding it better and if there are any recommendations. There is a fiber optic cable that comes directly into the building where it goes to a small cabinet. From the cabinet is a single fiber optic cable and it connects to a media converter with an RJ-45 cable plugging in and going to a switch. Now the media converter I believe is old (on the bottom of it says manufactured in 2010) and says 10/100 Mbps. The fiber internet coming in is capable of speeds of 100 Mbps.
    When I log into the web interface for the switch I notice it says "half duplex" for the port connecting to the media converter.
    My questions are :
    1) Because the media converter is half duplex and from what I hear can't be changed, does this slow down the internet speeds? I imagine I would want full duplex? If not, could someone explain why?
    2) Even though the fiber has max speeds of 100 Mbps would upgrading to a media converter with speeds allowing up to 1000 Mbps make a difference in my case?
    3) Any recommendations?

    Thanks very much.
     
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  3. zx10guy

    zx10guy Trusted Advisor

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    1) Yes, you want to operate at full duplex if at all possible. What full duplex means is both ends of the network connection can transmit and receive data at the same time.
    2) No. It doesn't work that way. Both ends of a network connection has to be able to support a given speed. To see if you can increase the speed of the fiber connection, you need to talk to whoever is providing this link to you. I assume it's some ISP. And assuming this ISP can give you a faster connection, you're going to be charged big time for it. This is above and beyond the other important details about the fiber connection itself. How long is the fiber run? What type of fiber is being used for your connection: single mode or multi mode? If it's multi mode, what type of multi mode fiber is it? 62.5 micron? 50 micron?
    3) My recommendation is unless there are actual performance issues with this circuit to leave it alone. You don't have enough technical knowledge to be messing with this working network connection.
     
  4. stockhouse50

    stockhouse50 Thread Starter

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    Hi, well when I log into the HP switch interface the port which the media converter is connected to shows many collisions. This is even after replacing the cable.

    Can you have full duplex if there is only one fiber optic cable coming from the cabinet? Or would there need to be two fiber optic cables in the setup?

    Thanks.
     
  5. zx10guy

    zx10guy Trusted Advisor

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    I would clear the counters for the port and then see if the collisions are occurring and incrementing.

    Duplex has nothing to do with a layer 1 situation. Duplex is a layer 2 concept. For that link to come up and function, the fiber would have to have both pairs operating. What you're probably seeing is a single fiber cable but it's actually two strands. If you look at it from one end of the fiber, one strand will be for transmit and the other will be for receive. On the media converter you should see a connector type that matches one of these:

    [​IMG]

    In the case of LC, you'll see a duplex connector layout like this:

    [​IMG]

    For SC, you'll see a duplex connector layout like this:

    [​IMG]

    With ST, it'll be obvious that you have two strands being connected to the media converter.

    The only other connector I've seen in use is MTRJ but I haven't seen a media converter which uses this interface.

    If you look on the media converter, you'll see a link light for the fiber connection. If the link light is not active, then you have a problem with the fiber. But since the port on the HP switch is up and transmitting data, chances are the fiber link is up and operational. Many media converters I've worked with won't bring up the copper/RJ45 port unless the fiber port is up and active.

    If the collisions persist, I would check to see what the HP port is set for in terms of duplex. I find many times port problems like this are a result of duplex and speed negotiation problems. If the HP port is set for auto, I would manually set those parameters and see if the problem persists.
     
  6. stockhouse50

    stockhouse50 Thread Starter

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    The collisions keep increasing each time I check. I was told in the past there were even more collisions occurring because of a duplex mismatch which has been corrected. When I hover over the port it currently says "Auto Negotiate 100 Mbps half duplex". If there was a duplex mismatch based on what your saying shouldn't this be set manually instead of auto negotiate?
    Also, Why doesn't auto negotiate match the duplexes and speeds properly?

    As for the fiber optic cable, it looks like a SC connector with a yellow cable. On the yellow cable it says SMF 9/125 which I believe means it's a Single Mode Fiber cable. I attached a photo of the cable although it's still plugged in.
     

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  7. zx10guy

    zx10guy Trusted Advisor

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    Yes. That's what I said above. If the port is set to auto and you're seeing rising collision counts, then manually set the port parameters for both speed and duplex.

    In general, auto negotiation usually works even when you're mixing different manufacturers. But there are times when one manufacturer implements the auto negotiation protocol a little bit differently that causes problems. I saw this quite a bit with 100 Mbit devices. I rarely if ever see this problem with Gigabit devices.

    Yes, it's an SC connector and yes, it's single mode fiber based on what you reported as the color of the outer jacket of the cable and the parameter of 9/125. The 9 means 9 micron which means the fiber is extremely thin. Compare this to the thinnest multimode fiber of 50 micron. Single mode fiber is used for long distance communications. Any thing associated with single mode is much more expensive than multimode components; the optics and the actual fiber. Based on this, to go Gigabit is going to be pretty expensive. You probably won't need to replace the fiber depending on the distance. But the media converter will have to be replaced to support both Gigabit and LX optics.
     
  8. stockhouse50

    stockhouse50 Thread Starter

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    Hi, so if I set the HP switch to 100 Mbps Full Duplex from Auto Negotiation and continue seeing collisions then I can verify that the media converter needs to be replaced? The only other option is "100 Mbps Half Duplex" which is what auto negotiation has the connection set as (Omitting the 10 Mbps connections). The CAT 5e cable was also replaced.


    Also, if I pull the fiber out and take a look to see if it is full duplex (see if there are two strands as you said) will this have any impact on any devices on the network (computers, multi-functional printers, switch or watchguard firebox m200 firewall or can I plug it back in and everything should just resume?

    Now the ISP says we can get speeds capable of 100 Mbps up/down and it's a dedicated line to this building. I've done speed tests on different day and I see speeds ranging from 45-60 Mbps. Is this typical because obviously 100 Mbps is theoretical but I thought we would get at least 80 Mbps with a dedicated line?

    Thanks.
     
  9. zx10guy

    zx10guy Trusted Advisor

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    I would try both settings (100Mbps/full duplex and 100Mbps/half duplex). I don't know what media converter brand you're using so I don't know if it has to operate at half or can operate at full. Another check is to move the cable the media converter is plugged into on the switch to another port that you know is working properly to see if the collisions keep climbing. If all of those fail, then trying a new media converter would be the next step. But if you were to do that, I would look into upgrading the HP switch to a switch which can support optics. In a project I used to work in, we used quite a few media converters primarily for printers because the building was wired with fiber. But at the switch we would have the fiber connections go directly into the switch as a media converter is an added component that can fail and complicate troubleshooting.

    Yes, if you, pull the fiber, you will break the network connection to your ISP. You don't determine if a connection can support full duplex by staring at the fiber. As I said before, you need to stop messing with this as your level of network knowledge is not enough to deal with this issue. You are going to seriously create a worse problem by fumbling around the way you are. I'm not saying this to be condescending. But based on your line of questioning and statements, it's clear you don't have the very basics you need to even attempt to use this as a learning experience. But to help out a little more, the picture you took of the SC fiber connection going into the media converter is only one fiber strand of the two required to make the circuit work. There is another SC fiber connection you didn't take a picture of which is right next to the one you did that is the other strand in the fiber pair. The two constitute a single fiber connection.

    With the ISP saying you can get speeds of up to 100Mbps, means you did not purchase 100Mbps service. While the circuit is running at 100Mbps, the ISP can set bandwidth limitations on your circuit to reduce the overall speed you have. Your company when they bought services from this ISP contracted for a certain level of service. You need to find out what that is. Those speeds you listed may very well be what your company is paying for. If your company is paying for faster service than what you're seeing, you need to see what the SLA (service level agreement) your company contracted with the ISP is.

    Again, you need to know your limitations especially in a business setting. Not admitting this and just winging things is a recipe for disaster. In the end, if things blow up because you did something which you had no business doing, your company will suffer and so will you professionally. It's smarter to admit you are in over your head and have your superiors either send you to get the proper training you need or to bring someone on as a consultant to work this specific problem. You can then work with this consultant to learn about the technologies at play here.
     
  10. stockhouse50

    stockhouse50 Thread Starter

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    Hi, I understand what you are saying and I'm not going to tamper with anything until I have the knowledge. If I don't feel comfortable I will work with a consultant.
    The picture I showed you is the only fiber optic cable going into the media converter. Other than that there are just two RJ-45 slots where one goes to the media converter and the other is labelled "ext mgmt". If this is the case then this media converter can only do half duplex? I attached an image of the media converter. On the back is just a power plug.

    With your experience with dedicated lines are you supposed to get the speeds you signed up for or can speeds fluctuate and by how much? Does the SLA usually say "you may not get these speeds" to cover themselves? I thought the whole point of a dedicated line is that you get the speeds you signed up for or is it just for the 99.999% uptime?

    Thanks and I really do appreciate all the knowledge provided.
     

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  11. zx10guy

    zx10guy Trusted Advisor

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    So I learned something by working through this thread. I did some research and that media converter does indeed only use one fiber strand. With normal fiber connections as I keep saying above, you normally have two strands of fiber. On one end, it's for transmit and receive while on the other end the roll of each strand is flipped to receive and transmit. This creates the needed bi directional pathway for communications. So how can your setup work with only one fiber strand when normally you need two for 100 Mbps connections? Well, your circuit from your ISP is utilizing a technology called BiDi (bidirectional). Setups like this take advantage of the fact a single fiber cable can support a bunch of different light wavelengths. One of the specs I pulled from a vendor of 100Mb single mode bidi optics are the wavelengths being used by that optic are 1310nm and 1550nm simultaneously on the same fiber strand. In a long winded way, I confirmed that your setup using a single fiber strand does indeed work. This adds to the complexity of the situation where not only are you dealing with single mode fiber which is already expensive in terms of the components needed to support it, but now BiDi is layered on top of this which adds to the cost. So I learned that there is BiDi technology available for 100Mb fiber. I've only seen BiDi used with frequency on 40Gbit connections because 40Gig when it was first introduced required a special fiber cable which has 8 strands of fiber. Not network implementations with existing fiber only have the 2 strand variety. Due to cost and distance constraints with the use of 4 pairs of fiber on 40 Gig, BiDi was implemented to allow 40 Gig to operate over normal 2 strand fiber cables.

    Getting back to you repeated question about duplex, you cannot determine what duplex a device supports by staring at the connection. This is a function of the device itself. I'll give a brief summary of duplex and why it's an important networking parameter as best as I can. Half duplex existed when Ethernet was first created. The reason for half duplex operation was because early Ethernet networks were all connected together over a hub which is just a fancy cable splitter. Because Ethernet networks cannot operate when two devices talk on the network at the same time, a protocol called CSMA/CD was created to detect and guard against frame collisions. When switches were created, the need for CSMA/CD was eliminated as the collision domain was reduced from the entire network to the host device and the switch. Since there is a guarantee only traffic between the switch and that connected host device will be on that wire, this allowed full duplex operation where both transmit and receive traffic can be sent at the same time without worry of any collisions.

    So again, you cannot know if full duplex operation is possible by just staring at the cable. You have to ensure both ends can support it. I looked up the media converter you are using and the specs do state it can support full duplex operation. In fact, the media converter is pretty much a layer 2 switch due to other protocols it supports such as VLAN tagging. One of the things you'll need to learn is to do an online search for information...particularly product information. You'll find that 9 times out of 10, you'll get answers to your questions.

    As for the dedicated leased line, you need to read the SLA to see what the ISP will guarantee.
     
  12. stockhouse50

    stockhouse50 Thread Starter

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    Ok now this is making more sense. So is this why on the media converter it says 1310 xmt / 1550 rcv which represents the different wavelengths it uses? I'm guessing "xmt" represents transmit and "rcv" represents receive.

    If I wanted too change the duplex mode of the media converter I would need to connect the cable with the rj-45 end in the ext mgmt port and the serial end to a computer with the iView management software (this is what I am seeing from the manual) ? I also see in the manual by default the device is given an IP 10.10.10.10 but our network uses a different network address so I'm not sure what the address is. If the port on the switch that is connected to the media converter is set as auto negotiation and shows as half duplex, then wouldn't I have to manually access the media converter configuration and change it from half duplex to full duplex? Is there a way to find the IP of the media converter if it's not the default IP?

    Are you saying that dedicated lines can have speeds that fluctuate?
     
  13. zx10guy

    zx10guy Trusted Advisor

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    Yes.

    Yes. You would have to access the media converter's management interface. Reading the manual, the media converters all ship from the factory with auto negotiation enabled. So as I said, setting those parameters on the HP switch may be enough to resolve the collision problems. In regards to the default IP address, just connect a laptop to the management port with an IP assigned in the same subnet. If you don't know the IP address to the media converter, then the only choice you have is to run a program that does an automated IP sweep trying all the different possible IP addresses. Who provided this media converter? Was it the ISP?

    I forgot to elaborate more on dedicated leased lines. If these circuits are point to point from one corporate location to another, then you should have consistent performance numbers. For this connection, it seems it's just for Internet access. Not sure what you're using as a metric to determine over all throughput. But you have to factor in user usage so testing the circuit when there is no or very minimal traffic on the circuit is crucial. Have you contacted the ISP to find out exactly what your company is paying for?
     
  14. stockhouse50

    stockhouse50 Thread Starter

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    If the media converter ships from the factory with auto negotiation enabled, and the port on the switch connected to the media converter is also set to auto negotiation, why does the switch show the port as "auto negotiation 100 Mbps half duplex" if both the switch and media converter are capable of 100 Mbps full duplex? Wouldn't it negotiate for full duplex? I will be trying full duplex on the switch to see if the collisions and speeds change.

    So I am trying to understand how to connect to the media converter. It looks like the media converter uses Iview2 management software so I downloaded it. I plugged a RJ-45 cable in the ext mgmt port and the other rj-45 end into the laptop. I ran the Iview2 software and it tries to scan for devices when launched. It didn't find any. I keep seeing rj-45 to serial in the manual but is that necessary? I don't have a serial port on any of my laptops.
    I tried running an IP sweep and it found pretty much every device but the media converter. Wouldn't it be on the same network as the switch?

    Also I found out that we 100 Mbps Fiber. There is a contract but nothing in the contract talks about speeds other than stating that we have 100 Mbps Fiber. I don't see the word SLA anywhere in the contract either. I tested the network when no one was using it and my download speeds top out at 4 MBps. A speedtest shows 65 Mbps.
     
  15. zx10guy

    zx10guy Trusted Advisor

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    I don't know how many times I can state this. I mentioned in one of my posts that I've seen auto negotiation problems between different manufacturers for 100Mb connections. I've stated numerous times the remedy for this is usually manually setting the port parameters on at least one of the devices connected together; sometimes it requires both sides to be set manually. I've stated numerous times to manually set the port parameters on the HP switch as it seems you have access to that switch and won't need to access the media converter. This is the last time I'm going to respond to this part of your posts as I've stated clearly what, why, and how.

    In regards to gaining management access to the media converter, if you don't have an idea of the network range, then it's literally trying to find a needle in a hay stack. The serial option is probably your only option. In the manual, it mentions an RJ45 to DB9 adapter. I haven't checked into whether this adapter is an industry standard configuration or if they use custom pinouts. If you want to make sure you don't have any problems gaining serial access, you would need to source the adapter from the manufacturer. From there, use a regular Ethernet cable to connect the adapter to the management port. On the computer side, you need to get a USB to DB9 adapter. Lastly, you'll need to run a terminal software. In the old days, I used to use Hyperterminal but now I use Putty.

    You would need to confirm with the ISP and get the details.

    You still haven't answered who provided the media converter. If it was provided by the ISP, you should be contacting them for support.
     
  16. stockhouse50

    stockhouse50 Thread Starter

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    I apologize for the repeat questions. I tried changing the port on the switch to full duplex and the collisions stopped. Thanks for the help. I still would like to access the media converter just to have that knowledge. I have a rj-45 to db9 cable but I need to get the usb to db9 cable. I downloaded the iview2 management software so wouldn't that be enough to detect the device when I use the cable with the adapter? I am not familiar with using putty.

    If everything on my network is using the 192.168.0.0 network, then why wouldn't the media converter also be on this network? It is a small building so I am aware of all of the devices and their IP addresses except for the media converter. I was wondering if I should dedicate a laptop to scan all the available private IP addresses using the IP sweeper program. Would this work?

    I think the media converter was owned by a previous small ISP company who has now been taken over by my current ISP. I called my ISP and they said are not responsible for it.
     
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