Etherchannel question

Hi!
I'm confused about the non-silent and silent option in the channel-group command.
If both end are configured with silent submode and auto mode, will the channel be established? Will the channel be established if both end are configured as silent mode, but one end with auto mode and the other end as desirabe?
Can i estabhlish a etherchannel without using PAgp or lacp? Is there any silent or non-silent sub mode in lacp?
There's one statement that i read from the cisco press book that i do not understand:
EtherChannel on mode does not send or receive PAgP or LACP packets. Therefore, both ends should be set to on mode before the channel can form.
What does that meant? Thks!

If both end are configured with silent submode and auto mode, will the channel be established?
>> No, if both sides are in auto mode, the channel will not and should not form - Per configuration guide auto on both sides will not established channeling as both ends are in passive negotiating state in which the port responds to PAgP packets it receives but does not initiate PAgP packet negotiation.
Will the channel be established if both end are configured as silent mode, but one end with auto mode and the other end as desirabe?
>>> Yes, same reason as above.
http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/sw_8_1/confg_gd/channel.htm#wp1033813
Can i estabhlish a etherchannel without using PAgp or lacp?
yes, in PaGP and LaCP are called "on". On this mode neither channel protocol will send "negotiation" to form channel as a result you need to turn mode "on" on both sides. And threfore once you force the channel to "on" there is really no PaGP nor LaCP being sent, hence, there is no PaGP nor LaCP.
Is there any silent or non-silent sub mode in lacp?
No, silent and non-silent modes are for PaGP.
http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/sw_8_1/confg_gd/channel.htm#wp1033813
There's one statement that i read from the cisco press book that i do not understand:
EtherChannel on mode does not send or receive PAgP or LACP packets. Therefore, both ends should be set to on mode before the channel can form.
>> See above the answer to your first question.
Please rate helpful posts.

Similar Messages

Stacking / Etherchannel Question

I have a network to install that was originally designed to be;
two distribution switchesthat are WS-C2960S-48FPD-L stacked. These are connected via two TEN Gig ports in etherchannel back to a 6513E.
The Access layer was to be 3WS-C2960S-48TS-L switches that were all stand alone, each with two, one gig uplinks one back to each of the distribution switches in an etherchannel. Now they would like the three access layer switches to be stacked. This access layer stack would have two, one gig uplinks in an etherchannel. One port of the etherchannel would land on switch 1 port 48 and the other port in the etherchannel would land on switch 3 port 48.
So I guess I really have three questions.
One can I hang a 2960 stack of three switches that are (access) off of a 2960 stack of two switches that is the (distribution)
Two Can I ethercahnnel between the two different stacks.
Third question is really configuration help.
The Etherchannel that I have between the Core 6513 E and the distribution WS-C2960S-48FPD-L is configured as follows:
On the 6513E
interface Port-channel6
description PS-*******-STK-0
switchport
switchport mode trunk
shutdown
platform qos trust cos
interface TenGigabitEthernet9/11
description UPLINK:PS-*******-STK-0-A
switchport
switchport mode trunk
shutdown
platform qos trust cos
udld port aggressive
channel-group 6 mode active
interface TenGigabitEthernet9/12
description UPLINK:PS-*******-STK-0-B
switchport
switchport mode trunk
shutdown
platform qos trust cos
udld port aggressive
channel-group 6 mode active
On the distribution switches WS-C2960S-48FPD-L
interface Port-channel6
description UPLINK<>CS-*******-0
switchport mode trunk
ip dhcp snooping trust
interface TenGigabitEthernet1/0/2
description UpLink<> CS-*******-0
switchport mode trunk
shutdown
udld port aggressive
channel-group 6 mode active
ip dhcp snooping trust
interface TenGigabitEthernet2/0/2
description UpLink<> CS-*********-0
switchport mode trunk
shutdown
udld port aggressive
channel-group 6 mode active
ip dhcp snooping trust
Does this above config look alright?
And would the following config work?
DistributionWS-C2960S-48FPD-L
interface Port-channel1
description DNLINK<>SS-*********-STK-0
switchport mode trunk
ip dhcp snooping trust
interface GigabitEthernet1/0/48
description DNLink<>SS-********-STK-0
switchport mode trunk
shutdown
udld port
channel-group 1 mode active
ip dhcp snooping trust
interface GigabitEthernet2/0/48
description DNLink<>SS-*********-STK-0
switchport mode trunk
shutdown
udld port
channel-group 1 mode active
ip dhcp snooping trust
Access Layer WS-C2960S-48TS-L (stack of 3 WS-C2960S-48TS-L)
interface GigabitEthernet1/0/48
description DNLink<>SS-*********-STK-0
switchport mode trunk
shutdown
udld port
channel-group 1 mode active
ip dhcp snooping trust
interface GigabitEthernet3/0/48
description DNLink<>SS-*********-STK-0
switchport mode trunk
shutdown
udld port
channel-group 1 mode active
ip dhcp snooping trust

Leo
I would be interested in the answer as well. I think, if i understand correctly, Mike doesn't mean the same end of the etherchannel, he means can you etherchannel from one stack to another stack. I thought this could be done but you know this stuff a lot better than me.
Is it a restriction on the switches ie. with VSS i believe you can run a MEC from one VSS pair to another which is effectively the same thing.
Jon

A few etherchannel questions

Hi All,
I am finally getting to replace our Dell POS switches. I am going to run VTP as well as etherchannel between a few floors. I have a few questions about etherchannel.
I will be running between a core 4507r and 3750 switches. i will stack 5 3750's on one floor and two on another.
my question, as i understand it you can run etherchannel from each switch in the stack to create a cross stack etherchannel correct? so in theory i could run an etherchannel on each switch in case one goes down? also, will all of these ports be in the same logical etherchannel? can i run trunking on these channels? being that i am doing cross channel i cannot run PAgP right? are there any issues with doing this between the 4507? also, is the "on" mode what most people use when they cannot use PAgP?
the 3750 config says these ports can be L3 ports so that I can assign an ip, how does this work if they are trunked ports? (isnt trunking L2?)
also, as a side note, it is best practice to keep all switches in a vlan together and off of the same vlan with users correct?
TIA,
R

my question, as i understand it you can run etherchannel from each switch in the stack to create a cross stack etherchannel correct?
YES.
so in theory i could run an etherchannel on each switch in case one goes down? also, will all of these ports be in the same logical etherchannel?
YES, but no more than 12 EtherChannels cannot be configured on a Catalyst 3750 switch stack.
can i run trunking on these channels?
YES.
being that i am doing cross channel i cannot run PAgP right?
cross-stack etherchannle using LACP or PAGP is not supported.
are there any issues with doing this between the 4507?
No, it's like channeling between 3750 and any otehr switch.
also, is the "on" mode what most people use when they cannot use PAgP?
Yes, since you cannot use negotiation to channel, your only option would be to turn it "ON".
the 3750 config says these ports can be L3 ports so that I can assign an ip, how does this work if they are trunked ports? (isnt trunking L2?)
Then you create an SVI for the trunked vlans. If they are L3 then you cannot trunk, right? You will say what about sub-interface? then why not channel at L2 and trunk that channel and create SVI?
I hope this answers your question.

Nexus 5000 Maximum Etherchannel question

I noticed that the documents say that the 5000 has a maximum number of 16 EtherChannels. Does this include vPCs? or are these counted seperately?

I agree that I think the documentation is incorrect. It can be found here...
http://www.cisco.com/en/US/docs/switches/datacenter/nexus5000/sw/configuration/nxos/Cisco_Nexus_5000_Series_NX-OS_Software_Configuration_Guide_appendix1.html

C4510R+E Etherchannel question

We have a Cisco 4510 access-layer switch with a pair of Sup8-E supervisor cards.
- The cards are configured so that slot5 is the active and slot6 is the standby Sup card.
- We have a pair of 10Gig trunks from Te5/1 and Te6/1 upstream to a Nexus 7009.
- The two uplink ports are configured as an Etherchannel.
Are we getting any benefit from the Etherchannel bundle since the Sup card in slot 6 is a standby and technically not passing any traffic? Is there any harm in leaving those ports in an Etherchannel bundle?
Thanks in advance.
Brian

I think, it is good idea to have the link from the stand-by sup in the port-channel. If for whatever reason the primary sup fails, the stand-by sup will take over and will forward traffic using the 10Gig link without any or minimum down time.
HTH

PORTCHANNEL/ETHERCHANNEL question

Hi Guys,
I have 2 sites site A and site B. Both are connected with TWO L2 WAN circuits. The L2 WAN circuits are terminated on separate devices. Will it possible to create etherchannel/Portchannel on 2 L2 WAN circuits to use them as one? Kindly provide your suggestions
Please see the attached image file for clarification.
Thanks

I think that you can create the etherchannel WAN link with layer 3 and PPP protocol.
If you have layer 3 router, the configuration is below :
controller E1 1/0/0
framing NO-CRC4
channel-group 0 timeslot 1-31
controller E1 1/0/1
framing NO-CRC4
channel-group 0 timeslot 1-31
interface Multilink1
ip address 192.168.253.214 255.255.255.252
no cdp enable
ppp multilink
ppp multilink fragment disable
ppp multilink links maximum 2
ppp multilink group 1

IDSM EtherChannel Question

In the config guide for the IDSM, it states:
To make sure that the same traffic is assigned to the two data ports on each IDSM-2, you must assign the
same EtherChannel index to both data ports on each of the IDSM-2s even though they are in different
EtherChannel groups.
Can anyone tell me how to change the EtherChannel index? I have successfully assigned the data ports to a port channel, but I cannot figure out how to change the EtherChannel index.

The 'note' mentioned in the configuration guide is a little misleading. By index they mean interface index of the data port (1 or 2). At least this is my understanding.
e.g.
intrusion-detection module 4 data-port 1 channel-group 5
intrusion-detection module 4 data-port 2 channel-group 6
intrusion-detection module 5 data-port 1 channel-group 5
intrusion-detection module 5 data-port 2 channel-group 6
They are just telling us not to worry about the 'two' data ports of the IDSM-2 being in TWO different etherchannel groups. We have to make sure that 'first data port' on both IDSM-2 is assigned to the same group and the second data port (data-port 2) is assigned to the same group and not mix it around like this:
intrusion-detection module 4 data-port 1 channel-group 6
intrusion-detection module 4 data-port 2 channel-group 5
intrusion-detection module 5 data-port 1 channel-group 5
intrusion-detection module 5 data-port 2 channel-group 6
Please rate if helpful.
Regards
Farrukh

Fundamental question on etherchannel hashing.

Folks,
I had some very basic questions on the way hashing takes place on Cisco switches connected to each other over a port channel.
Considering that 2 links are used between the switch, namely port Gi 0/1 and Gi 0/2.
1) By default I understand that this could be a L2 etherchannel or L3 etherchannel, the default mode of hashing is still the Source and destination MAC id, am I correct?
2) So now if the source IP of 1.1.1.1 needs to reach to 1.1.1.2 how would the hashing calculation take place? Again I understand that this is on the basis of the last 3 bits from the IP address field. 001 and 010 come to 011 which is 3. So based on the number of ports it will select which interface to assign.
I still do not understand what has the below output got to do with the selection:
Core-01#sh interfaces port-channel 40 etherchannel
Age of the Port-channel   = 204d:07h:40m:10s
Logical slot/port   = 14/3          Number of ports = 2
GC                  = 0x00000000      HotStandBy port = null
Passive port list   = Te1/4 Te2/4
Port state          = Port-channel L3-Ag Ag-Inuse
Protocol            =    -
Port security       = Disabled
Fast-switchover     = disabled
Fast-switchover Dampening = disabled
Load share deferral = disabled
Ports in the Port-channel:
Index   Load      Port          EC state       No of bits
------+------+------------+------------------+-----------
0      E4            Te1/4                 On   4
1      1B            Te2/4                 On   4
Time since last port bundled:    204d:07h:19m:44s    Te2/4
Time since last port Un-bundled: 204d:07h:19m:54s    Te1/4
Core-01#
What does that load-value mean? and how is that calculated? and does that have a role to play in the selection of the port?
Thanks,
Nik

Disclaimer
The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.
Liability Disclaimer
In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.
Posting
So it looks like how to divide the bits is decided by the switch.
Ah, yea, reread my original post for answer to your second question. ;)
An actual hashing algorithm can be rather complicated. What they try to do is to "fairly" divide the input value across the number of hash buckets. For example, if you have two Etherchannel links, they will try to hash the hash attribute such that 50% goes to one link and 50% to the other link.
For example, assuming you hash on source IP, how do you hash 192.168.1.1, .2, .3 and .4? A very simple hash algorithm could just go "odd"/"even", but what if your IPs were .2, .4, .6 and .8? A more complex algorithm would try to still hash these IPs equally across your two links.
Again, hashing algorithms can get complex, search the Internet on the subject, and you may better appreciate this.
Because of the possibility of such complexity, one vendor's hashing might be better than another vendor's, so they often will keep their actual algorithm secret.
No matter, though, how good a hashing algorithm might be, they all will hash the same attribute to the same bucket. For example, if you're still using source IP, and only source IP, as your hash attribute, all traffic from the same host is going to use the same link. This is why what attributes are used are important. Choices vary per Cisco platform. Normally, you want the hash attributes to differ between every different traffic flow.
Etherchannel does not analyze actual link loading. If there are only two active flows, and both hash to the same link, that link might become saturated, while another link is completely idle.
Short term Etherchannel usage, unless you're dealing with lots of flows, is often not very balanced. Longer term Etherchannel usage, should be almost balanced. If not, most likely you're not using the optimal hash attributes for your traffic.

Question about configuring Etherchannel on Catlyst 3750

Hi, I have a stack witch catalyst 3750, I mean I have 3 switches ( 1 master, 2 slaves)
My question
Can I configure an etherchannel having 2 interfaces on each switch?
How can I do this?
Thanks
Regards

If you have a stack it should present itself as a single switch just put channel-group 1 desirable nonsilent if you are going to another cisco on each of the interfaces you want in the channel . this is for a layer 2 etherchannel . For a layer 3 etherchannel is somewhat more involved and too long to write here , just go to the cisco.com site and search on configuring etherchannels,3750 .

Etherchannel - Config Question

First time configuring etherchannel. I have followed the documentation, watched videos, etc. The channel is up, but wanted to verify I did it right - and have not missed something.
Scenario:
Connecting a brand new 3650X into a 3750. The 3750 is the "Core" and does the layer 3 routing, etc. The 3650 is going to become a new Server Backbone - should participate on VLAN 10 only. All servers in our data farm will connect into it (eventually).
Normally we just create one trunk port on each switch and call it done (we do not have a big data farm/and or IT team) but I wanted to start looking at Etherchannel, etc.
Config - Core:
interface GigabitEthernet2/0/12
description ***Trunk to 203 - Server Backbone***
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 10
switchport mode trunk
switchport nonegotiate
channel-group 1 mode on
interface Port-channel1
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 10
switchport mode trunk
switchport nonegotiate
Server Backbone:
interface GigabitEthernet1/0/1
description ***Server Backbone - Switch 3 - Trunk***
switchport trunk allowed vlan 10
switchport mode trunk
switchport nonegotiate
channel-group 1 mode on
interface Port-channel1
switchport trunk allowed vlan 10
switchport mode trunk
switchport nonegotiate
(Does not have the encapsulation command, as not available in that IOS - assuming it is automatic?).
Basically I am looking to improve throughput and redundancy. Is there anything else I should add and/or change about what was configured?
(NOTE: I know these may or may not be the best switches to use - but they are what we can afford on our budget).

Disclaimer
The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.
Liability Disclaimer
In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.
Posting
Well, of course, you want more than one link in your port-channel, both for additional aggregate bandwidth and additional redundancy.
You may want to review whether you're using the optimal hashing algorithm for your port-channel.

Dummy question - Vlan brought by etherchannel

Hello,
I have 2 switches and 1 etherchannel between the 2 switches. VLAN 15 is trunk'd through etherchannel from sw1 to sw2. Now I want to use the VLAN 15 on the second switch. What should I do in order to be able to use the vlan on the second switch. These switches are 6500 and there is no use of vtp.
Regards.

Hi
If you have a routed interface on sw2 for vlan 15 is it "down down" ?
Without a layer 2 vlan your layer 3 vlan 15 interface on sw2 should not be up.
Run a "sh vlan" on sw2 and make sure vlan 15 does not exist.
HTH
Jon

Question Callmanager works with etherchannel

Hi,
is possible callmanager works with etherchannel?
Regards.

I don't think so, but even if it does, what would the benefit ?
You can have a regular dual-NIC config for redundancy.

Need Help!!! Question about Etherchannel

Greetings All,
Has anyone here ever experienced shuting down the Port-Channel Interface of a switch but still for some reason the switches still pass traffic?

Mmmmm in theory that should not happen - what happens when you shut for port-channel on both sides, still see traffic?
Do you have another connection between the devices other than the ether-channel?
HTH>

Question on etherchannel non-silent option....

What is it for?
The cert guilde I am using makes no sense.
All it says is "The silent setting is for connections to file servers or packet analyzers".
TY!

Read the below for more clarification
http://www.cisco.com/en/US/tech/tk389/tk213/technologies_tech_note09186a00800949c2.shtml#silent
HTH>

Layer 3 etherchannel - load 0x00

folks
i have a quick question i'm hoping you can help with
i have a layer 3 etherchannel between 2 * 3750G stacks, both clusters use gi1/0/25 and gi/2/0/25 for the etherchannel and both are set as 'on'
i have traffic passing over the link but i get the following output from a show etherchannel detail
there are no bits being recorded and the load is 0x00
can someone help to explain this please?
thanks to anyone taking the time to reply
Group: 10
Group state = L3
Ports: 2   Maxports = 8
Port-channels: 1 Max Port-channels = 1
Protocol:    -
Minimum Links: 0
                Ports in the group:
Port: Gi1/0/25
Port state    = Up Mstr In-Bndl
Channel group = 10          Mode = On              Gcchange = -
Port-channel = Po10        GC   =   -             Pseudo port-channel = Po10
Port index    = 0           Load = 0x00            Protocol =    -
Age of the port in the current state: 10d:01h:43m:57s
Port: Gi2/0/25
Port state    = Up Mstr In-Bndl
Channel group = 10          Mode = On              Gcchange = -
Port-channel = Po10        GC   =   -             Pseudo port-channel = Po10
Port index    = 0           Load = 0x00            Protocol =    -
Age of the port in the current state: 10d:01h:43m:54s
                Port-channels in the group:
Port-channel: Po10
Age of the Port-channel   = 10d:01h:45m:24s
Logical slot/port   = 10/10          Number of ports = 2
GC                  = 0x00000000      HotStandBy port = null
Passive port list   = Gi1/0/25 Gi2/0/25
Port state          = Port-channel L3-Ag Ag-Inuse
Protocol            =    -
Port security       = Disabled
Ports in the Port-channel:
Index   Load   Port     EC state        No of bits
------+------+------+------------------+-----------
0     00     Gi1/0/25 On                 0
0     00     Gi2/0/25 On                 0
Time since last port bundled:    10d:01h:43m:54s    Gi1/0/25

Hi,
I guess this is just a hardware limitation on the 3k platforms (ASICs).

Etherchannel question

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