13

Yes, configure it, just because your port channel is good doesn't mean your entire topology necessarily is - just connect another cable between the two switches on an active VLAN and watch the badness happen. I recommend MST (Multiple Spanning Tree) providing the switch supports it - interoperable, backwards compatible and of course, has the obvious benefit ...


8

According to the FastIron config guide: If the primary interface of a trunk is enabled for monitoring, the entire trunk will be monitored. You can also enable an individual trunk port for monitoring using the config-trunk-ind command Trunk in this sense being the FastIron term for an aggregated interface. If this didn't work you could use a TAP, or ...


8

The power of 2 requirement varies per vendor/hardware/software. Cisco had (has) a pretty bad stigma against them with a lot of the earlier catalyst switches capable of 10G. The problem comes with how the software hashes (or "balances") data over the multiple ports in the port-channel (this is agnostic of PAgP or LACP). This post does an excellent job of ...


7

LACP gives you a significant advantage in that it verifies connectivity in both directions over each link. You can think of it as also combining the features of UDLD with link aggregation. For example, imagine you have the links configured in "mode on". Now lets say one of the links from the 3750 to the 2960 fails but in only one direction, say the ...


7

Improperly configured EtherChannel (port-channel) interfaces would be disabled automatically, to prevent problems such as loops. First of all, having the same configuration on each side would be the safest. Here's a checklist: Both switches must see the ports as an EtherChannel bundle. If one switch would consider ports as separate connections, it's ...


6

You will need real switches since there is no emulator for their ASICs. GNS3 can emulate only routers (and run their IOS images). You can try Cisco Packet Tracer for switches, but keep in mind that it is a simulator and it does not have full set of features you will find on real equipment.


6

Is it possible to view the configuration of the ports of all switches in the network by plugging the console cable to one switch As they are independent, free-standing switches, No. If they were in a stack or cluster, then the answer most likely would be yes -- they'd all appear as one switch.


6

Packet tracer is a simulation for Network academy not a IOS emulator (like say GNS3) if there is a conflict between the doc and packet tracer, packet tracer looses. If you read further in the documentation a LOT of things have to match for an etherchannel bundle can form and link speed is one of them. A corner case MAY be etherchannel autonegotated ports ...


5

Without further information, the encircled links indicate channel bonding/trunking. Bonded channels (or LAG trunks, Etherchannel) are regarded as a single, logical link. STP doesn't block any of the physical links. Even if the physical links to a server are not bonded, there's only half a bridge loop: the switch forwards frames solely based on the ...


4

Indeed, enable spanning-tree. The 2810 is standard MST by default. Depending on how you have your trunks configured (Trunk vs. LACP), the individual ports could still create a loop. Call it insurance... you may never need it, but the one time you do and it's not there, you'll regret it. (Other networking mistakes could also create a loop.)


4

No it isn't. The reason why you can see VLANs on both switches is VTP (VLAN Trunk Protocol)


4

Look at this link and scroll about half way down. http://forums.networkinfrastructure.info/nortel-ethernet-switching/ers-8300-and-lacp-with-hp-blade-servers/ UPDATE: Fixed - Here's how you get LACP to work with the 8300. The configuration is simple, for a base line. Configure your ports and vlans as you would normally (for multiple vlans enable tagging ...


4

Link aggregation / port-channel / lacp will not allow you to have a single stream to use several interfaces. Four different streams can use different physical interfaces, and each one could use 1Gbs (reaching 4Gbs total) but none of them will be able to achieve more than 1Gbs. Those protocols works with an algorithm that will choose a specific interface ...


4

first of all you need to know that using port channel mean you will maximum obtain one physical link speed (1G) per flow where flow means same source port and same destination port, so if you generate 2 traffic flow you will obtain speed of two physical link and so on . Versification there are two verification methods 1. from cisco side "show port-...


4

We don't have router, all we have L2 switch network. We have many servers behind trunk, so should i use src-dsp-ip? or src-dst-mac ? You need to weigh several factors to determine which method to use in different places on your network. Different network engineers will come up with different recommendations. This is really leading to opinion-based answers,...


3

The best way to find out is to determine the version of IOS that your switch is running. show version will get you this information. Then look up the version of IOS using Cisco's Feature Navigator. You will be able to determine what exactly your version of code supports and what it does not.


3

If the port channel is DOWN, then the Cisco device doesn't see it bundled together. As your display shows, each port are Stand-Alone (as indicated by the "I" status), meaning they're seen as separate entities to the switch with regards to MAC table, etc. This point to something wrong in your channel config and/or capabilities (mismatch between the linux box ...


3

PAgP silent permits the channel to be formed, but PAgP packets can still be interpreted by the device that is set to silent. Imagine the case with some devices that do support PAgP but may not enable it on a "secondary" LAG, but you still want this LAG to be online in the event of a failure so you can switch over to it. You could force the channel on, ...


3

Is the requirement of 2n number of ports for EtherChannel a critical requirement or just a recommendation to ensure, perhaps, an even load balancing? Most vendors don't have such a requirement. This is a convention often discussed based on the limitations of a three bit hash when load balancing. I personally disagree with this stance, but I will get ...


3

Whether Cisco, HP or another provider, with any form of link aggregation, multiple physical ports are treated as a single logical port, after all that is the whole point of link aggregation. Just be careful of terminology used by OSes such as bonding or teaming since they may or may not be doing link aggregation depending on the configuration. As to ...


3

As per default, etherchannel is running in "silent" mode. So ethch goes up at the first time, but if you try to disable/enable on side maybe ethch doesn't goes up again. From CISCO CCO : non-silent —(Optional) If your switch is connected to a partner that is PAgP capable, configure the switch port for nonsilent operation when the port is in the auto or ...


3

Sadly portchannels on Cisco are a pain when adding new interfaces. Sometimes the only way to "recover" a Port-Channel is to completeley deconfigure and reconfigure it. Steps to do so: Reset all channel interface members to their default config default interface TenGigabitEthernet1/1/2 default interface TenGigabitEthernet2/1/2 Remove the channel interface ...


3

One possible answer is because the top switch in the diagram is the root switch. The other switches have their root ports connected to the root switch. That means the etherchannel will be blocking to avoid a loop. Here's a general algorithm that STP uses. The root switch has all its ports designated (i.e. forwarding). Every other switch selects the port ...


3

Yes, this should work since the channel is switch-to-switch ethernet from the perspective of the switches. If you don't actually need to negotiate the channel, why use a channel negotiation protocol? That's just one more unnecessary complication. With Cisco switches on each side of the channel, why not just use the channel-group <num> mode on ...


3

The big problem with this is out-of-order packets and statistically half your traffic flowing across a slower, more loss-prone link. If you can do L3 (ip) across both links, I would suggest "CEF per-packet" load balancing. But again, half the traffic would be crossing a slower link. (I'm not sure CEF uses link bandwidth.) What you have is an unequal cost ...


3

L3 EtherChannel and VLAN/Trunk concepts DO NOT work together. In this scenario, you should use L2 EtherChannel between L3-1 and L3-2 switches. Ensure that you create all L3 Int VLANs / L2 VLANs, and trunk them on this L2 EtherChannel between L3-1 and L3-2 switches.


2

Even in real hardware, the HWIC-4ESW and 16ESW modules do NOT support LACP/PAgP In order to play with these sorts of tech you'll need a regular Cisco switch that support it or another vendor of course


2

I wouldn't see any point in enabling STP in this situation. STP prevents loops between switches with multiple links. In this case you're using a trunk (in the HP parlance) which will be treated as a single link so STP would not be needed.


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