VxLAN | Part 3 - Spine Leaf Topology

now the story of on what network with distributed hosts and the one technology has no choice but to keep them all together is VX Lane welcome back to part three of the vehicle and series it's been great to have you along for the first two parts of this series and I'm glad to see you coming back for more so far we've covered the basics of VX land including encapsulation tunnels and v-n eyes in the last video we looked at how the VX lane headers work this video is focused on the spine leaf topology often called a fabric this is an architecture that is often associated with VX land it's not exclusive to VX land though fabric path and ACI are other technologies that may use spine leaf but before we do that let's get started by looking back at the traditional network architecture you you may already be familiar with the traditional hierarchical architecture it uses core distribution and access layers the access layer is where hosts and devices connect the distribution layer controls traffic in an area perhaps a floor in a building and the core layer provides fast transport between areas this model is often used in the campus and sometimes in the data center it creates Network pods and focuses on a north-south traffic pattern where the majority of traffic needs to leave the local area traffic moves up through the layers and travels back down to reach its destination this model can be used in different ways one way is to route all the way to the access layer there are many benefits to this but it can restrict mobility if a device like a smartphone moves from one area to another it needs to get a new IP address through DHCP the other option is to span VLANs across the access layer this increases mobility but also increases the broadcast and failure domain size this will also only work within a distribution block as the core is a routed network this is a good topology for the campus where a DHCP server can easily hand out new IP addresses in the data center we typically have hosts with static addresses using this model here can really limit mobility imagine you have different subnets in each rack and you want to migrate a VM it would need to change IP address this is where the spine leaf architecture along with VX Lane comes in you spine leaf is not new he's also called a closed or closed network as it was originally designed by Charles Clos in the 1950s as a better way to switch telephone calls I sincerely hope I've pronounced Charles name correctly if I'm wrong please let me know in the comment section this architecture has only two layers the spine layer and the leaf layer the leaf layer is where hosts and other devices connect the leaf switches connect to the spine switches no other devices connect to the spine as they exist only for passing traffic every leaf switch has a link to every spine switch each of these links are routed making them all layer 3 every link needs an IP address at each end and will use a slash 30 or slash that you want the subnet a routing protocol like OSPF or AI GRP is used to manage routing what all of this means is that every path is equal and every destination is always two hops away if a link or switch fails ecmp is used to recover nearly instantly you may notice that there are no links between spine switches and no links between leaves this keeps the topology consistent and avoids unnecessary paths the exception to this is if you are using V PC in this case a pair of switches can have a layer 2 P link and a layer 3 keepalive link added these extra links are used for VPC traffic only spine leaf is well-suited to the data center it is a routed Network which limits the layer to failure domain adding vex land over the top allows devices to move without changing IP addresses this also focuses on an east-west traffic pattern this suits the data center has a lot of the traffic is between servers another major advantage is scalability need to add more hosts just add more leaf switches need more bandwidth at a spine switch or to the critical point here is that the design doesn't change you just need more switches links and IP addresses the routing protocol will take care of the rest you in part one of this series we discussed how V X LAN is an overlay technology running on top of an IP network or underlay the spine leaf fabric becomes the underlay of the X LAN the V types are on the leaf switches this means that V excellent tunnels are created between leaf switches the spine switches are used mainly for transport they may also be used as multicast at rendezvous points if you use BGP the spine switches can become route reflectors but more on that in part 4 you so now we have a nice fabric for our hosts how do we add Internet and when connectivity what about firewalls load balancers and routers this functionality is added to the leaf layer leaf switches with routers and firewalls attached are called border leaves the border leaf switches represent connectivity to and from the fabric this is also where routes from the overlay are redistributed into the core routing protocol in practice these switches are not particularly special hosts can still be connected to border leaves what happens if your fabric is growing out of control one option is to break it into smaller fabrics these can be connected with a super spine this behaves just like a normal spine layer of course you'd need to have a very large fabric to use the super spine topology in the fourth part of this series we'll look at how the host addresses are learned how V tips are discovered and the difference between data plane and control plane learning please hit the subscribe and notification buttons I'd also really like to get your feedback on this video please leave me a comment so know what you thought and I'll see you in part 4 you

Channel: Network Direction

Views: 95,670

Keywords: benifits of leaf spine designs, vxlan in spine leaf, routed leaf and spine, vxlan part 3, advantages of spine leaf networks, spine leaf topology undrlay and overlay network, spine and leaf network, spine-and-leaf architecture, clos layer 2, clos topology, spine leaf, advantage of vxlan, leaf and spine architecture, spine and leaf architecture, ingress replication, spine leaf architecture, spine and leaf design, spine and leaf configuration, leaf spine, spine and leaf

Id: x1F-RCW9fqo

Length: 8min 21sec (501 seconds)

Published: Thu Feb 15 2018