Hello. Welcome to Dell EMC Networking Solutions Engineering.
In this video, we will be taking a look at deploying
Layer 2 Leaf-Spine architecture with Dell EMC XC series.
Hyper-Converged Infrastructure or HCI
is a software defined architecture with integrated
compute, software defined storage, networking and virtualization.
It decouples compute, storage and networking
from underlying infrastructure.
Dell EMC XC Series Hyper-Converged Appliances
integrate Dell EMC PowerEdge Servers, Nutanix software
and a choice of factory installed hypervisor.
With flexible combinations of CPU, memory,
SSD or HDD, and global support by Dell EMC,
they are ideal for enterprise business applications, server virtualizations,
hybrid or private cloud projects and Virtual Desktop Infrastructure.
XC Series has a fault tolerant architecture
and self-healing capabilities,
leading to system reliability and data integrity.
The traditional networking three layer tree, consists of access,
aggregation and core layers.
A major issue in datacenters include
increasing east-to-west traffic and scaling effectively
as the business grows.
East-to-west traffic is the traffic within the datacenter.
Clos or Leaf-Spine network,
is becoming widely adopted, as it is designed
to minimize the number of hops between the hosts.
Every leaf switch is connected to every spine switch.
All leaf switches are just one hop away from each other.
This minimizes latency and bottlenecks in the network.
The leaf spine architecture is highly scalable.
As we add more racks to the datacenter,
a pair of leaf switches are added to each rack.
Spine switches are added as bandwidth need increases.
Each rack has a pair of leaf switches.
They are in VLT.
Every leaf switch is connected to every spine switch.
In rack 1, leaf 1 is connected to spine 1 and 2.
Leaf 2 is connected to spine 1 and 2.
Similarly in Rack 2, leaf 3 is connected to spine 1 and 2.
Leaf 4 is connected to spine 1 and 2.
The connections between leaf and spine switches
can be Layer 3 or routed, or they can be layer 2 or switched.
In this video, we will be looking at
layer 2 architecture.
The leaf pair in each rack,
and the spine switches are in VLT.
VLT provides high availability, eliminates spanning tree blocked ports,
provides layer 2 multi pathing and load balances traffic.
In the layer 3 architecture, the traffic between leaf and spine is routed.
That is, L2-L3 boundary is at leaf switches.
The spine switches are never connected to each other.
ECMP is used to load balance traffic across Layer 3 network.
Leaf switches in each rack are in VLT.
Connections within the racks from hosts to leaf switches
are Layer 2.
There are a few considerations
while choosing the type of leaf-spine architecture
that you want to implement in the data center.
Layer 2 or switched architecture,
puts everything in a single broadcast domain.
Since Layer 3 architecture involves routing,
it breaks up broadcast domain.
The spine switches are in VLT,
and hence limited to two switches at the Spine layer.
Layer 3 topology allows the addition of Spine switches
as the bandwidth needs grows,
and hence Layer 3 is much more scalable.
Overlay network utilizing VXLANs such as VMware NSX,
require a Layer 3 underlay network.
Ultimately, choosing a Layer 2 or Layer 3 is a matter of preference
and it requires careful consideration of advantages and disadvantages,
of each architecture type.
The protocols, used in Layer 2 architecture
are Rapid Spanning Tree Protocol (RSTP), Link Aggregation Control Protocol (LACP),
Uplink Failure Detection (UFD), Virtual Link Trunking (VLT).
RSTP is used as a precaution to prevent loops.
VLT environment by nature are loop free,
but using Spanning tree as a precautionary measure
is considered best practice.
LACP is used to aggregate ports into a LAG.
Port channels are created between leaf and spines.
UFD automatically detects the loss of upstream connectivity
and shuts down downstream ports.
VLT allows physical links between two switches
to appear as a single virtual link to other switches.
For more information, please refer to your switch user guide.
Let’s take a look at the topology used in this Layer 2
leaf-spine example.
S4048-ON are used as leaf switches
and S6010-ON are used as spine switches.
The leaf pairs in rack 1 and 2 are in VLT.
Spine 1 and 2 are in VLT as well.
Port channels 101, 102, and 103
connects to node 1, 2 and 3 of the XC cluster.
Port channel 1 from Leaf 1 and 2 VLT pair
connects to spine 1 and 2 VLT pair.
Similarly, port channel 2 from leaf 3 and 4 VLT pair
connects to spine 1 and 2 VLT pair.
Leaf 3 and 4 switches connects to a R630 server
using port channel 101.
VLAN is configured across the switches.
We are using VLAN 10 in this example.
A virtual machine is created on one of the XC cluster node.
All the nodes in this XC appliance run VMware ESXi.
In order to follow the configuration easily,
the topology diagram will be displayed often
while looking at the switch CLI.
The initial switch configurations involves
setting the hostname, enabling LLDP,
enabling RSTP, setting the management IP address
and the default route.
These initial configurations
are implemented across all the switches used in this example.
The next step is to configure VLT.
Ports 49 and 50, are used as VLTi interconnects.
Bring these ports up by issuing a no shut command.
Configure port channel 127 for VLTi
and add the member ports 49 and 50.
The next step is to create VLTi domain.
Add the peer link port channel, port channel 127.
Provide the back-up destination as management IP address of leaf 2,
and provide unit ID as 0.
Ports Te 1/1 to Te 1/3 connects to XC nodes.
Issue the no shut command on these ports.
The ports Te 1/1 to Te 1/3 on leaf 2 are initially kept shut down,
until teaming and failover is configured on vSphere web client.
Add ports Fo 1/51 and Fo 1/53 into port channel 1 using LACP.
Issue the no shut command on these ports.
The next step is to configure the port channels.
Configure port channel 1.
Use switchport command to make it into layer 2
and enable port mode hybrid.
For port channels 101,102, and 103,
in addition issue the spanning tree rstp edge port command,
since they are connecting to the XC appliance.
It is very important to issue the VLT peer lag port channel command
to ensure that the port channels operate as expected.
The next step is to configure VLAN.
The final step is to configure UFD.
If uplinks to the Spine fails, then ports to servers will be shut down.
Let’s take a look at Leaf 3 in rack 2.
After performing the initial basic configurations,
no shut port te 1/48.
Te 1/48 connects to a R630 server.
Issue the no shut command on the VLTi interconnect ports.
Configure interfaces Fo 1/51 and Fo 1/53
as a port channel and add it into port channel 2 using LACP.
Issue the no shut command on these ports.
The next step is to configure port channel 2 and port channel 101.
Port channel 127 is used for VLTi port channel.
Configure VLAN 10 and tag port channel 2
and untag port channel 101.
VLAN 10 is configured and used in all switches.
The final step is to configure UFD.
If uplinks to the spine fails,
then the ports to the server R630 will be shutdown.
Let’s look at spine 1 configuration.
After finishing the initial configurations, such as hostname,
LLDP, enabling RSTP, configure the interfaces
that are used for port channel 1.
Do note that spine 1 will be forced to act as a root bridge
in RSTP, by setting the bridge priority to 0.
Configure the interfaces that are used for port channel 1.
Interfaces fo 1/25 and fo 1/26
are added into port channel 1,
while interfaces Fo 1/27 and 1/28 are added into port channel 2.
The interfaces are added into port channel using LACP.
Issue the no shut command on these ports.
Ports 31 and 32 are used as VLTi interconnects.
Port channel 127 is used for VLTi port channel.
The next step is to create VLT domain.
The next step is to configure port channel 1 and 2.
Use switchport, portmode hybrid.
Most importantly, issue the VLT peer lag port channel command.
The final step is to configure vlan 10 on this switch.
Similarly on Spine 2, configure interfaces
25 and 26 into port channel 1
and the interfaces 27 and 28 into port channel 2.
Issue the no shut command on the VLT interconnect ports
Fo 1/31 and Fo 1/32.
Configure port channels 1 and 2.
Port channel 127 is used as VLTi port channel.
Finally, configure VLAN 10.
Validating the leaf spine setup
involves commands that verify the configurations.
For VLT, use show VLT brief.
ICL link status, heart beat status
and VLT peer status, should all be Up.
Use show VLT mismatch to identify any VLT issues.
Use show spanning tree rstp brief
to view the rstp details.
To verify port channel created using LACP,
use show LACP summary.
To dig deeper into port channel,
issue show LACP followed by the port channel number.
Let’s look at Leaf 3 to display the VLAN information.
Show VLAN displays the VLANs configured on the switch.
Note that VLAN 10 and its associated ports are displayed.
On spine 1, verify the VLT configuration.
Use show spanning tree rstp brief, to view the rstp details.
Note that spanning tree rstp displays spine 1 as the root.
This is because spine 1 was to forced to act as the root
by setting the bridge priority as 0.
To verify port channels created using LACP,
use show LACP summary.
To dig deeper into port channel, issue show LACP,
followed by the port channel number.
Ensure that similar commands are run across
all switches in this example to verify the configuration.
For more information, please refer to your switch user guide.
The final validation is to set perform a ping test
between the virtual machines in XC nodes and the R630 server.
The nodes in the XC cluster run VMware ESXi.
Windows server 2016 is the name of the virtual machine that was created.
In this example, IP address 172.16.1.6 is set on the R630 server.
IP address 172.16.1.7 is set on the virtual machine
on the XC node.
Ping 172.16.1.6 from the virtual machine
and 172.16.1.7 from R630 server.
In this video, we looked at deploying layer 2 leaf-spine architecture
along with the XC appliance.
Thanks for watching this video.
For additional information on deploying Layer 2 leaf-spine architecture
and deploying XC series, click on the links in the description,
For more networking solutions, visit the
Dell Networking TechCenter.
Lastly, do not forget to check out the layer 3 leaf spine video.