Ether-Channel or "How we lied to Spanning-Tree"
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- Опубликовано: 2 окт 2024
- This video walks through taking 2 or more physical interfaces at L2, and making them appear as 1 larger logical interface, so that spanning-tree will be able to use all of the bandwidth provided by both links.
Hi-
Etherchannel is the "idea" or concept of bundling multiple physical links into one larger logical bundle. PAgP is a Cisco method can use to negotiate the bundle. LACP is an industry standard to do the same thing. LACP is indeed preferred as it is a cross vendor standard.
Does that help?
I could see Keith Barker at the club jamming to that intro music.
Great video! IOS posts so many messages!!!. I got some questions:
1. If 1 link on the EtherChannel goes down, it still works as normal?
2. If both links goes down on the EtherChannel and after a while they both go up, EtherChannel operation resumes? or PortChannel 1 will be shut and then I'll need to manually bring it up?
Supposing links goes down b/c of a cable failure or shutdown commands.
Thanks.
tinypic.com/r/29vgc1x/9
How would you setup EtherChannel for sw3, sw4, sw5 to sw1 & sw2?
and EtherChannel between sw1 and sw2?
thanks
Great question.
In the previous video, I set up inter-vlan routing, using a multi-layer switch (The switch which has L3 interfaces, and supports IP routing.
So in summary, the routers are integrated inside the switches.
Check out the previous video's on inter-vlan routing I have on RUclips, and let me know if you still have questions.
Best wishes,
Keith Barker
How’s the stp behave if we introduce a new single gig link between 1st and middle switch? Considering 3rd switch is the root. I assume there would be path recalculation but would that cause a cpu hike in a big network.
Thank you Sreelakshmi Sasi. Feel free to join my Discord sever. Lots of people there helping each other out. Each Saturday at 10am Pacific I hold my "Office Hour" where learners can ask questions about the topics they are studying. Mostly focusing on Cisco CCNA 200-301 topics. Feel free to join us there live if you are available. Here is the link ogit.online/Join_OGIT_on_Discord
Thanks again Sreelakshmi Sasi!
my favourite CCIE ...
1. Yes. If you 'shut' any one interfaces from the Etherchannel, it still remain in the 'up' state. Else if the Etherchannel were to go down with one interface down, there is no change from the earlier STP converging scenario except speed.
2. Assume links fa0/1 and fa0/2 in an Etherchannel between S1 and S2. If I 'shut' both Fa0/1 and 0/2 on S2, the ports go down=>port-channel1 down=>etherchannel down. But even if I turn on only Fa0/1 =>port-channel 1 is up(by itself)=>Etherchannel is up.
The thing that bugs me about etherchanel is the load-balancing algorthims. If you only have a single IP/MAC as the destination or source then no load balancing will occur in that direction. You can solve this problem with layer 3 routing protocols, but with layer 2 port-channel I have yet to find a way. Sometimes it would be really useful to do. If you know how, please do let me know :-)
nice work , and thank u
How can you ping the 30 network with no router?
Russell ping is not a Router function 2 pcs cabled together can ping each other because windows machines have an IP STACK loaded as drivers ( with a NIC Card) in the OS. However switches these days have Router functions , they can do Layer 3 functions.
Hi Kieth,
one simple question!!
What are the constraints on channel-group number? Does that number compulsorily need to match on the two switches that happen to be having the two physical interfaces that are the part of the same EtherChannel?
One thing to note .. using "on" compared to :"active" a misconfigured link could cause a loop with "on". Also it might be a good idea to enable "spanning tree etherchannel guard misconfig" so in the event that there is a cabling issue you are less likely to take down the network in the event of a cabling mistake..
Thanks for the video. isn't Cisco suggest not to use mode ON on both side?
LACP Active/Active or LACP Active/Passive would normally be preferred to on. In this demo, I used switchport modules in IOS routers in GNS3 as an emulator, and they didn't support LACP. :)
Thanks to Keith's VCP6 videos I usually find myself in situations where spanning tree is no longer is a threat. But still there's no better person to learn the concept from!
Keith,
I can truly say your videos are changing my life!! Im a very visual and physical learner so when I read a concept it may not fully sink in but when I read and view your videos, that big light bulb goes off in my head and it sinks in. I know you have heard it many times but you are an angel sent from the networking Gods!! Thank you for blessing us newbies with your teachings and knowledge.
Great explanation Keith, I follow your videos and they helped me understand the dark side of many aspects.
Could you add access lists to that switches scenario - for example to allow server on right to see all Vlan 2 devices and other site to see only specific port on the server in Vlan3?
Thanks, you have a teaching gift filled with humor.
very good but i want to know how auto-negotiate speed and duplex occur between tow ports ?
I just learn some good stuff. How to default interfaces, how to us the range command to configure multiple etherchannels.
Dear Keith Barker .you are my super teacher god bess the way you teach us ..great tribute from my side sir.
Keith is a legend
Thank you Anthony Donov!
I think it was a great video .. you talked at a just fine speed.
Thankyou for the help, keep up the awesome videos, this helped me with assignment so much :)
Keith - Thank you so much for yet another great demonstration
The video is well explained, thanks
LACP seems to be the recommended option nowdays? From speaking to people in networking, Etherchannel is not really used anymore? I am not sure how true/untrue this is but as LACP is not Cisco specific it would make sense.
If you've a chance could you clarify between the two as I have yet to find a clear answer online in relation to this, as etherchannel is described as dynamic in LACP in some articles.
Thanks
Use LACP Active/Active .....do no't do anything else solves the problem .
Great video!! Your explanation sure helps!
@CommanderBR : pleasure :)
Hello Keith,
Great video and thank you for sharing. I have a question regarding the physical interfaces and I may have missed it and if I did I apologize ahead of time. I noticed that there is no trunking information configured on the physical interfaces just the channel-group assignment. Does the physical interfaces inherit the trunking information that in associated with the logical port channel? So whatever you configure under the logical interface will be on the physical interfaces rather it being access or trunking?
Hello Marcus-
The video began with the physical interfaces already configured as individual trunks. In the video, I defaulted the interfaces and then made them members of the port-channel. In the logical port-channel interface configuration, the configurations we apply there (such as trunking) are replicated to the member interfaces automatically.
Thanks,
Keith
Keith Barker
Got it! Thanks a million for sharing your knowledge.
@astalavistasandy thx for the help!