What ports can be configured as an EtherChannel?
After the formation of a channel, the configuration of any port in the channel as a trunk applies the configuration to all ports in the channel. Identically configured trunk ports can be configured as an EtherChannel. You must have all ISL or all 802.1Q; you cannot mix the two.
How does EtherChannel work between two devices?
One EtherChannel link always connects the same two devices only. The individual EtherChannel group member port configuration must be consistent on both devices. EtherChannel technology only bundles ports of the same type. On a Layer 2 switch, EtherChannel is used to aggregate access ports or trunks.
What are the criteria for forming an EtherChannel?
Criteria – To form an EtherChannel, all ports should have: EtherChannel protocols – To form an EtherChannel, there are 2 protocols, port aggregation protocol (PAgP) and link aggregation control protocol (LACP). 1. Port Aggregation Protocol (PAgP) – Port Aggregation Protocol is a Cisco proprietary protocol used to form an EtherChannel.
What happens if one link in EtherChannel goes down?
If one link in EtherChannel goes down, the bandwidth of the EtherChannel will be automatically updated, and thus the STP cost will change as well. On Layer 3 switches, you can convert switched ports to routed ports. You can also create EtherChannel links on Layer 3 links. Layer 3 port channels are discussed in more detail in Chapter 5.
What is the difference between a port-channel and a trunk?
Port channels enable several physical links to be combined into one aggregated logical link. Trunking enables a link to carry (trunk) multiple VLAN traffic.
Does a port-channel need to be trunk?
A portchannel can be a bundle of links that are all in the same vlan or it can be a bundle of links that are all trunk links. It can't be a combination of both.
Which can not be made in an EtherChannel?
You can create an EtherChannel link between two switches or between an EtherChannel-enabled server and a switch, but you cannot send traffic to two different switches through the same EtherChannel link.
Is EtherChannel a Layer 2 or 3?
A layer 3 EtherChannel is similar to an interface on a router. The switch won't “switch” traffic on this interface but route it. Because it's a layer 3 interface, we configure an IP address on it.
Can a port be both access and trunk?
So you could configure a port as both a trunk (with "switchport trunk" statements) and an access port (with "switchport access" statements). When the link negotiates as a trunk, it will have the correct trunk configuration and if it doesn't negotiate as a trunk, it will have the correct access configuration.
Which port can be used as trunk?
VLAN-enabled ports are generally categorized in one of two ways, tagged or untagged. These may also be referred to as "trunk" or "access" respectively. The purpose of a tagged or "trunked" port is to pass traffic for multiple VLAN's, whereas an untagged or "access" port accepts traffic for only a single VLAN.
What are some of the restrictions of an EtherChannel?
Limitations. A limitation of EtherChannel is that all the physical ports in the aggregation group must reside on the same switch except in the case of a switch stack, where they can reside on different switches on the stack.
What is the difference between EtherChannel and port channel?
An etherchannel bundles individual physical links into one logical link to increase the total bandwidth. It also seen as one link by Spanning tree algorithms. A port channel is the logical representation of the etherchannel on the switch.
What is difference between EtherChannel and vPC?
vPC (Virtual Port-Channel) also known as multi-chassis ether channel (MEC) is a feature on the Cisco Nexus switches using which you can configure port-channel across multiple switches (i.e vpc peers). Here you can see that Virtual Port channel (vPC) is configured using the interfaces of two switches.
Does EtherChannel need IP address?
A layer 3 etherchannel is similar to an interface on a router. The switch won't “switch” traffic on this interface but route it. Because it's a layer 3 interface, we configure an IP address on it. Before we configure the port channel settings you need to make sure that all interfaces have the exact same configuration.
Is LACP the same as port channel?
LACP is used for the collective handling of multiple physical ports that can be seen as a single channel for network traffic purposes. packets. A port in passive mode cannot set up a port channel (LAG. A LAG combines a number of physical ports together to make a single high-bandwidth data path.
How many interfaces can EtherChannel have?
You can configure up to 48 EtherChannels, depending on how many interfaces are available on your model. Each channel group can have up to 16 active interfaces, except for the Firepower 1000, 2100, Secure Firewall 3100 models, which support 8 active interfaces.
Why is a trunk port necessary?
A trunk port allows you to send all those signals for each switch or router across a single trunk link. In contrast to an access port, a trunk port must use tagging in order to allow signals to get to the correct endpoint. Trunk ports typically offer higher bandwidth and lower latency than access ports.
What does it mean when a port is trunked?
A trunk port is a type of connection on a switch that is used to connect a guest virtual machine that is VLAN aware. Generally, all frames that flow through this port are VLAN tagged. The exception to this is when a trunk port is granted access to the untagged VLAN set (native VLAN ID).
Do trunk ports need a VLAN?
Trunk links are required to pass VLAN information between switches. A port on a Cisco switch is either an access port or a trunk port. Access ports belong to a single VLAN and do not provide any identifying marks on the frames that are passed between switches.
Is an uplink port a trunk port?
An uplink port would be used to pass traffic to another switch or router or network device. A trunk port would be used to pass VLAN traffic between two switches or other network devices.
How does etherchannel work?
EtherChannel provides incremental speeds between Fast Ethernet (FE) and Gigabit Ethernet (GE) through the group of multiple equal-speed ports into a logical port channel. EtherChannel combines multiple FEs up to 800 Mbps or GEs up to 8 Gbps. The combination provides fault-tolerant, high-speed links between switches, routers, and servers. Trunking carries traffic from several VLANs over a point-to-point link between the two devices. The purpose of the configuration of trunking between the switch and the router is to provide interVLAN communication. In a campus network, you configure trunking over an EtherChannel link to carry the multiple-VLAN information over a high-bandwidth channel.
What is the show etherchannel command?
The show etherchannel command displays EtherChannel information. The command also displays the load-balance or frame-distribution scheme, port, and port channel information. The command syntax is:
What is native VLAN?
Note: Native VLAN is the VLAN that you configure on the Catalyst interface before you configure the trunking on that interface. By default, all interfaces are in VLAN 1. Therefore, VLAN 1 is the native VLAN that you can change. On an 802.1Q trunk, all VLAN packets except the native VLAN are tagged. You must configure the native VLAN in the same way on each side of the trunk. Then, the router or switch can recognize to which VLAN a frame belongs when the router or switch receives a frame with no tag. In the diagram in this section, VLAN 10 has been configured as the native VLAN. For interVLAN routing, be sure to configure the default gateway on all workstations that connect to the switches. This default gateway is the IP address that you configure on the subinterface. You create a subinterface on the router for each VLAN. In this example, workstation1 has been configured with default gateway 10.10.10.1. This gateway is the IP address of subinterface port channel 1.10. Workstation2 has been configured with default gateway 10.10.11.1. This gateway is the IP address of subinterface port channel 1.20.
How many Ethernet channels does a Cisco router support?
Each of these modules supports a maximum of six EtherChannels, with up to eight ports in an EtherChannel bundle.
What command to use to verify trunk configuration?
You can use the show interfaces interface.subinterface command in order to verify the trunk configuration.
What command to use to verify port channel?
You can use the show interfaces port-channel channel-number command in order to verify the port channel interface and the channel member ports.
What is the show interfaces interface-id trunk command?
The show interfaces interface-id trunk command displays the trunk configuration of the interface.
Does STP block redundant switches?
But, as you connect the switches with more than one link, STP (Spanning Tree Protocol) will block the least redundant link. As we have made an EtherChannel, all the links (that are grouped as one logical link k) will be treated as single logical link therefore no link will be blocked and also, it will provide us high speed link and redundancy in our network.
Can switchport mode trunk be used on both switches?
Here, user has used the mode desirable and switchport mode trunk. The modes should be same on both switches therefore user will configure this on other switch also.
Can you bundle more than one link into one logical link?
By forming an EtherChannel, you can bundle up more than one link into a single logical link. But, as you connect the switches with more than one link, STP (Spanning Tree Protocol) will block the least redundant link. As we have made an EtherChannel, all the links (that are grouped as one logical link k) will be treated as single logical link ...
What is an etherchannel?
EtherChannel is a technology wherein we bundle physical interfaces together to create a single logical link. It is also known as Link Aggregation. It provides fault-tolerant and high-speed links between Cisco switches and routers and is often seen in the backbone network. The approved open standard is called 802.3ad, which works with other vendors and is often called LAG.
How Does EtherChannel Work?
We can assign up to 16 physical interfaces to an EtherChannel, but only 8 interfaces can be active at a time. You can form EtherChannel between two, four, or eight active Fast, Gigabit, or 10-Gigabit Ethernet interfaces, with an additional one to eight inactive interfaces which can become active as the other interfaces fail.
Why is Etherchannel used?
Since more than one physical connection is combined into one logical connection, EtherChannel enables more available links in instances where one or more links go down.
What are the benefits of etherchannel?
Meaning, we can utilize all of the 4 links and reap the benefits of EtherChannel namely, load balancing, redundancy, and increased bandwidth.
How many protocols can we use for EtherChannel?
We also have two protocols that we can use, aside from manually configuring EtherChannel.
Can you use STP to avoid Layer 2 loops?
But, in a traditional network setup, Spanning Tree Protocol (STP) blocks one redundant link to avoid Layer 2 loops. Our solution to this problem? EtherChannel.
Does Cisco offer round robin load balancing?
Cisco does not offer round-robin load balancing for EtherChannel as it could potentially result in out-of-order frames.
Set up trunk ports on all switches using DTP
You’ll need to set up trunk ports using dtp between all of the switches. Switch1s port connecting to router1 should also be a trunk link. Then verify the trunk connections.
Use VTP to Populate VLANs
VTP is not on the current CCNA exam objectives. However, I’ve seen this in the real world so it’s good to know how it works and how to configure it.
Final VLAN Pieces
Now that your trunks and VLANs are configured. You can assign some ports to the VLANs. Then block the unused VLAN 100 on all of your trunk links.
Spanning Tree Protocol
This is a very simplified Spanning Tree lab. Leave a comment if you’d like a more detailed one in the future.
Etherchannel (Layer 2)
You’ll need to make sure that all of the Etherchannel ports are either in access mode or trunk mode. It cannot be a mix of both. Also, I had an error (twice) in Packet Tracer where the P01 interface was stuck on STP listening mode. It would not resolve until I reset Packet Tracer.
Breaking the Lab
Now that your LAN is complete. I’ve taken the liberty of breaking it. Your job is to troubleshoot and fix the lab so that PC1 can ping both PC2 and PC3. There are 3 things to fix that are keeping the PCs from pinging eachother.
Summing it All Up
You can now set up trunks, VLANs, router on a stick, etherchannel, and more. Doing these labs will help solidify knowledge. Most likely things will not work as expected the first time through. You’ll learn even more trying to fix these issues.
How does etherchannel work?
EtherChannel reduces part of the binary pattern that the addresses in the frame form to a numerical value that selects one of the links in the channel in order to distribute frames across the links in a channel. EtherChannel frame distribution uses a Cisco-proprietary hashing algorithm. The algorithm is deterministic; if you use the same addresses and session information, you always hash to the same port in the channel. This method prevents out-of-order packet delivery.
Why does the EtherChannel switch use the same MAC address?
So if the data is received from the same source, then same link of the EtherChannel is used in order to forward the data.
How many Ethernet ports can a Catalyst 3750/3560 support?
The Catalyst 3750/3560 series switch can support up to eight compatibly configured Ethernet interfaces in an EtherChannel. The EtherChannel provides full-duplex bandwidth up to 800 Mbps (Fast EtherChannel) or 8 Gbps (Gigabit EtherChannel) between your switch and another switch or host. With Cisco IOS Software Release 12.2 (20)SE and earlier, the number of EtherChannels has a limit of 12. With Cisco IOS Software Release 12.2 (25)SE and later, the number of EtherChannels has a limit of 48.
How many ether channels can a Cisco 6500/6000 switch support?
Catalyst 6500/6000 switches that run Cisco IOS? system software support a maximum of 64 EtherChannels. You can form an EtherChannel with up to eight compatibly configured LAN ports on any module in a Catalyst 6500/6000 series switch. All LAN ports in each EtherChannel must be the same speed, and you must configure all the ports as either Layer 2 or Layer 3 LAN ports.
How does Cisco hash work?
The Cisco-proprietary hash algorithm computes a value in the range 0 to 7. With this value as a basis, a particular port in the EtherChannel is chosen. The port setup includes a mask which indicates which values the port accepts for transmission. With the maximum number of ports in a single EtherChannel, which is eight ports, each port accepts only one value. If you have four ports in the EtherChannel, each port accepts two values, and so forth. This table lists the ratios of the values that each port accepts, which depends on the number of ports in the EtherChannel:
What is a fast Ethernet channel?
Fast EtherChannel allows multiple physical Fast Ethernet links to combine into one logical channel. This allows load sharing of traffic among the links in the channel as well as redundancy in the event that one or more links in the channel fail. Fast EtherChannel can be used to interconnect LAN switches, routers, servers, and clients via unshielded twisted pair (UTP) wiring or single-mode and multimode fiber. This document refers to Fast EtherChannel, Gigabit EtherChannel, port channel, channel and port group with a single term, EtherChannel. The information in the document applies to all of these EtherChannels.
How many ports does a WS-X6148-GE-TX have?
You can also run into the oversubscription problem if you have four WS-X6148-GE-TX or WS-X6148V-GE-TX modules that run at 100 Mbps with 48 EtherChannels, and each channel has 4 ports (1 port per module).
What is etherchannel in networking?
EtherChannel is a technology that allows you to circumvent the bandwidth issue by creating logical links that are made up of several physical links.
Why is etherchannel active?
Where there is only one EtherChannel link, all physical links in the EtherChannel are active because spanning tree sees only one (logical) link. If one link in EtherChannel goes down, the bandwidth of the EtherChannel will be automatically updated, and thus the STP cost will change as well. NOTE.
What is an Ethernet channel?
EtherChannel is a technology that was originally developed by Cisco as a LAN switch-to-switch technique of grouping several Fast or Gigabit Ethernet ports into one logical channel. This technology has many benefits:
What happens when only one address is hashed?
If only one address or port number is hashed, a switch looks at one or more low-order bits of the hash value. The switch then uses those bits as index values to decide over which links in the bundle to send the frames.
Why does a spanning tree block one switch?
When several EtherChannel bundles exist between two switches, spanning tree may block one of the bundles to prevent redundant links. When spanning tree blocks one of the redundant links, it blocks one EtherChannel, thus blocking all the ports belonging to this EtherChannel link.
Can you have different load balancing methods for different etherchannels on one switch?
Default configuration can differ from switch to switch, but commonly the default option is src-dst-ip. It is not possible to have different load-balancing methods for different EtherChannels on one switch. If the load-balancing method is changed, it is applicable for all EtherChannels.
Can you send traffic to two different switches through the same ether channel?
You can create an EtherChannel link between two switches or between an EtherChannel-enabled server and a switch, but you cannot send traffic to two different switches through the same EtherChannel link.
Introduction
Prerequisites
- Requirements
Before you attempt this configuration, note these requirements: 1. The FEC and 802.1Q trunking features are available on the Catalyst L2 fixed configuration switches in Cisco IOS® Software Release 12.0(5.2)WC(1) and later. The Catalyst 2940 and 2955/2950 switches do not support Int… - Components Used
This configuration was developed and tested with these software and hardware versions: 1. Catalyst 2950 switch that runs Cisco IOS Software Release 12.1(9)EA1d 2. Cisco 7200 router that runs Cisco IOS Software Release 12.2(3) The information in this document was created from th…
Background Theory
- EtherChannel provides incremental speeds between Fast Ethernet (FE) and Gigabit Ethernet (GE) through the group of multiple equal-speed ports into a logical port channel. EtherChannel combines multiple FEs up to 800 Mbps or GEs up to 8 Gbps. The combination provides fault-tolerant, high-speed links between switches, routers, and servers. Trunking carries traffic from s…
Configure
- In this section, you are presented with the information to configure the features described in this document. For explanations of the commands in the document, refer to these documents: 1. Configuring EtherChannelson Catalyst 2950 2. Configuring VLAN Trunks section of Configuring VLANson Catalyst 2950 3. Configuring Fast EtherChannel section of Configuring LAN Interfaces…
Verify
- This section provides information that you can use to confirm your configuration works properly. Certain show commands are supported by the Output Interpreter Tool (registered customers only) , which allows you to view an analysis of showcommand output.
Related Information