when you're configuring a router interface a switch interface or an interface that's in your local computer there are number of options available in this video we'll look at some of those interface configurations we can start with the basic connectivity that we have to the network when we plug in an ethernet cable there are a number of ethernet settings we need to consider and two of the most important are the ethernet speed and the duplex the speed is obviously going to be how fast this conect connection is going to run this might be a 10 megabit connection 100 megabits 1,000 megabits which would also be 1 gig connection 10 gig or even faster we have to be sure that this configuration is the same on both sides so if we have a computer that's connecting to a switch the speed on both of them has to be configured the same in many cases we would set this to automatically configure itself so you can simply plug in any device and the switch will automatically adjust to the configured speed the other option we might have available is either half duplex or full duplex in most cases this is also set to automatic but if you do set these manually on both of these devices you have to make sure that both of them are set to be the same if you have the speeds mismatched on both sides the connection will not work at all you'll never get a link light but if you mix the duplex configuration where one side is set to half duplex and the other side is set to full duplex you'll find the connection does operate but you'll notice that it is not quite as efficient as it should be and in fact you'll have very poor performance if you start putting a lot of traffic over that link this is why one of the initial configurations we'll look for when we're troubleshooting ethernet is the speed and the duplex and make sure that they're the same on both sides of the connection if those match then we'll shift our Focus to the Internet Protocol or the IP configuration for that interface face this might be an ethernet connection it might be a VLAN config we might be setting up management interfaces and all of these will need an IP address a subnet mask a default gateway and perhaps other IP configurations as well these will usually be values that have been assigned by a network administrator so we'll want to configure and make sure that the IP address subnet mask default gateway DNS settings and everything else matches the configuration that we've received from our admin if this configuration doesn't match what we've been given let's say we've used a different default gateway IP address or we put in the incorrect subnet mask then we may find that we're not able to connect to other IP devices on this network fortunately this is a relatively easy configuration to validate we can simply look at what we've been given and look at what we've configured in the system and make sure that both of those match another useful configuration especially between switches would be one for link aggregation this is sometimes referred to as Port bonding or you might see it abbreviated as lag for link aggregation this means that we are connecting multiple interfaces together on these two devices which normally we would not want to do because we would be creating a loop but if you've configured all of those interfaces as link aggregation the switch will interpret them as one very large connection rather than four individual connections so if all four of these were gigabit Ethernet connections between this switch we would configure those as lag and you now have 4 gigabits of throughput to be able to communicate between those two devices some switches will support an automatic configuration of this link aggregation using a protocol called lacp This is the link aggregation control protocol this allows you to Simply configure the interface as lacp plug in the interfaces and all of the underlying link aggregation configs will automatically configure themselves between those two devices if you were to capture traffic between these two devices you would see lacp traffic being transferred from one switch to the other to be able to have the most efficient communication from one device to another we need to be able to send packets across that will not be fragmented along the way since we don't always know what networks are located between the two devices there may be times when our data is fragmented mented and therefore is less efficient to transfer across the network fragmenting a packet tends to slow down the overall communication and if we lose one of those fragments then we have to resin the entire frame again normally the determination of the most optimal MTU or maximum transmission unit is done automatically when you first connect to a device but sometimes filtering and firewalls won't allow the automated process to work properly and you may need to manually configure an MTU on your system system on some networks we're not trying to minimize the size of our communication instead we're trying to maximize the size of our frames and one of the ways we can do that is through a method called jumbo frames ethernet frames by default are 1500 bytes in length if we're transferring large amounts of data we may want to increase the size of those frames to make the communication that much more efficient and with jumbo frames you can increase the size of an Ethernet frame up to 9 9,216 bytes of an MTU on many devices you'll find that they'll use 9,000 as the accepted highend of a jumbo frame in fact here is the configuration from my computer that says that I can configure frame sizes on my network to be between 1280 and 9,000 bytes this means I can transfer a single frame that contains the same amount of information as six normal frames on the same network this means there are fewer pack to have to switch or route through my network and I can transfer much more in a shorter amount of time the challenge though is all of the devices that are in that Communications path must understand jumbo frames so all of your switches all of your routers and the other devices your communicating to have to also be configured to use these jumbo frames if there is any device in the middle of this communication that doesn't understand jumbo frames then they will drop these frames and you won't be able to communicate to that device at all