Tag :: EVPN

As of EOS 4.22.0F, EVPN all active multihoming is supported as a standardized redundancy solution.  Redundancy

In an EVPN network, unique route targets are assigned to each VLAN (or a VLAN bundle). For an IRB (Integrated Routing and Bridging) configuration, unique route targets are assigned for each L3-VRF as well.These route targets are statically configured for each VLAN (or a VLAN bundle) and each L3-VRF as well. Starting with 4.35.1F, such route targets for L3-VRFs can now be auto-derived from the corresponding VNI numbers.

Route reflectors are commonly used to distribute routes between BGP peers belonging to the same autonomous system. However, this can lead to non-optimal path selection. The reason for this is that the route reflector chooses the optimal route based on IGP cost from its perspective. This may not be optimal from the perspective of the client as its location may be different from the RR

This feature extends the BGP Layer 3 VPN Import/Export and VRF Route Leaking functionality to “default” VRF.

This feature enables efficient cross-domain communication in a multi-domain deployment where the Layer 2 leaf VTEPs don't have arp learning bridged configured. Without this feature, cross-domain ARP requests must be flooded across all domains, creating significant overhead in large multi-domain deployments.

S supports L3 EVPN gateway with Type 5 nexthop-self mechanism. While the nexthop-self mechanism is simple to operate, the L3 gateway lacks the support to rewrite the EVPN route distinguisher as well as the BGP route target. This feature supports an alternative L3 EVPN gateway mechanism using multi-domain L3 VRF instead. A multi-domain IP VRF allows configuring not only the local domain route distinguisher (RD) and route targets (RT), but also the remote domain route distinguisher and route targets on a DCI gateway.

To use IPv6 addresses for VXLAN underlay, there are two different approaches.  The first approach is to make use of

In a Service Provider network, a Provider Edge (PE) device learns VPN paths from remote PEs and uses the Route Target

This feature allows a Data Center (DC) operator to incrementally migrate their VXLAN network from IPv4 to IPv6

As described in the Multi-VTEP MLAG TOI, singly connected hosts can lead to suboptimal peer-link utilization. By adding a local VTEP to each MLAG peer, the control plane is able to advertise singly connected hosts as being directly behind a specific local VTEP / MLAG peer.

RFC7432 defines the MAC/IP advertisement NLRI (route type 2) for exchanging EVPN overlay end-hosts’ MAC and IP address reachability information. When an EVPN MAC/IP route contains more than one path to the same destination, the EVPN MAC/IP best-path selection algorithm determines which of these paths should be considered as the best path.

In the Centralized Anycast Gateway configuration, the Spines are configured with EVPN-IRB and are used as the IP Default Gateway(DWG), whereas the Top of rack switches perform L2 EVPN Routing.

This feature enables support for Macro Segmentation Service (MSS) to insert security devices into the traffic path

This new feature explains the use of the BGP Domain PATH (D-PATH) attribute that can be used to identify the EVPN domain(s) through which the EVPN MAC-IP routes have passed. EOS DCI Gateway provides new mechanisms for users to specify the EVPN Domain Identifier for its local and remote domains.   DCI Gateways sharing the same redundancy group should share the same local domain identifier and same remote domain identifier.

Multihoming in EVPN allows a single customer edge (CE) to connect to multiple provider edges (PE or tunnel endpoint). In any multihoming EVPN instance (EVI), for each ethernet segment a designated forwarder is elected using EVPN type 4 Ethernet Segment (ES) routes sent through BGP. In single-active mode, the designated forwarder (DF) is responsible for sending and receiving all traffic. In all-active mode, the DF is only used to determine whether broadcast, unknown

E-Tree is an L2 EVPN service (defined in RFC8317) in which each attachment circuit (AC) is assigned the role of Root or Leaf. Root ACs can communicate with leaf ACs and other root ACs. Leaf ACs can only communicate with root ACs. Leaf AC to leaf AC traffic is blocked. In this implementation, ACs are configured at the VLAN level, and the forwarding rules are enforced using a combination of local configuration of leaf VLANs (for local hosts), and asymmetric route targets (for remote hosts).

Ethernet VPN (EVPN) is an extension of the BGP protocol introducing a new address family: L2VPN (address family number 25) / EVPN (subsequent address family number 70). It is used to exchange overlay MAC and IP address reachability information between BGP peers within a tunnel

EVPN route advertisements carry RD and RT. RD (Route Distinguisher) : prepend to the tenant’s IP Prefix or MAC address to make it globally unique. RT (Route Target) : a BGP extended community used to tag the EVPN route.  The EVPN import policy is chosen to select what is the target tenant VRF is imported from the global EVPN table.

In the traditional data center design, inter-subnet forwarding is provided by a centralized router, where traffic traverses across the network to a centralized routing node and back again to its final destination. In a large multi-tenant data center environment this operational model can lead to inefficient use of bandwidth and sub-optimal forwarding.

This feature adds control plane support for inter subnet forwarding between EVPN and IPVPN networks. It also

In the traditional data center design, inter-subnet forwarding is provided by a centralized router, where traffic traverses across the network to a centralized routing node and back again to its final destination. In a large multi-tenant data center environment this operational model can lead to inefficient use of bandwidth and sub-optimal forwarding.

This feature adds control plane support for inter subnet forwarding between EVPN networks. This support is achieved

This feature is available when configuring Layer2 EVPN or EVPN IRB.As described in RFC7432 section 15 [1], “MAC Mobility” or “MAC move” occurs when a Customer Edge (CE) moves from one Ethernet segment to another, resulting in two EVPN MAC/IP (Type 2) routes being advertised -- one route with the previous Ethernet segment ID (ESI) and the other with the new Ethernet segment ID. MAC mobility also happens when a CE moves from a single-homed provider edge (PE) to a different PE.

“MLAG Domain Shared Router MAC” is a new mechanism to introduce a new router MAC to be used for MLAG TOR Leaf pairs. The user can either explicitly configure the MAC address of their choice or use the system-generated MLAG system-id for this purpose.  

EVPN MPLS VPWS (RFC 8214) provides the ability to forward customer traffic to / from a given attachment circuit (AC) without any MAC lookup / learning. The basic advantage of VPWS over an L2 EVPN is the reduced control plane signalling due to not exchanging MAC address information. In contrast to LDP pseudowires, EVPN MPLS VPWS uses BGP for signalling. Port based and VLAN based services are supported.

In network deployments, where the border leaf or Superspine act as PEG and it is in the transit path to other multicast VTEPs, the multicast stream will not pass since the border leaf will decapsulate the packet even if it doesn't have a receiver. This transit node is called the Bud Node. The device should be able to send decapsulated packets to any local receivers as well as send the encapsulated packets to other VTEPs

EOS currently supports EVPN Multicast by setting up PIM tunnels in the underlay with VXLAN as the transport. While this is an efficient delivery mechanism, it requires PIM to be deployed in the underlay. In certain cases, the overheads of provisioning/maintaining the multicast routers and the multicast routing state in the underlay may be significant. To support such scenarios, Ingress Replication (IR) or Head-End Replication (HER) can be used in the underlay to distribute overlay multicast traffic.

EVPN Multihoming defines a mechanism for Multihoming PEs to quickly signal, to remote PEs, a failure in an Ethernet Segment (ES) connectivity with the use of Ethernet A-D per ES route

Multihoming in EVPN allows a single customer edge (CE) to connect to multiple provider edges (PE or tunnel endpoint). These PE devices are all connected to the same Ethernet-Segment (ES). Multihoming is activated by assigning a unique Ethernet Segment Identifier (ESI) and ES-Import Route Target (RT) which enables all the PEs connected to the same multihomed site to import the Type 4 ES routes

Multihoming in EVPN allows a single customer edge (CE) to connect to multiple provider edges (PE or tunnel endpoint). The default mode of operation is all-active, in which the CE connects using link aggregation and can send traffic to either PE by hashing (or any other means) and expect the traffic to be successfully delivered.

In EVPN, an overlay index is a field in type-5 IP Prefix routes that indicates that they should resolve indirectly rather than using resolution information contained in the type-5 route itself. Depending on the type of overlay index, this resolution information may come from type-1 auto discovery or type-2 MAC+IP routes. For this feature the gateway IP address field of the type-5 NLRI is used as the overlay index, which matches the target IPv4 / IPv6 address in the type-2 NLRI. Other types of overlay index are described in RFC9136, but these are currently unsupported.

As described in the L3 EVPN VXLAN Configuration Guide, it is common practice to use Layer 3 EVPN to provide multi

Flexible cross-connect service is an extension of EVPN MPLS Virtual Private Wire Service (VPWS) (RFC 8214). It allows for multiplexing multiple attachment circuits across different Ethernet Segments and physical interfaces into a single EVPN VPWS service tunnel while still providing single-active and all-active multi-homing.

In EOS 4.22.0F, EVPN VXLAN all active multi homing L2 support is available. A customer edge (CE) device can connect to

Ethernet VPN (EVPN) networks normally require some measure of redundancy to reduce or eliminate the impact of outages and maintenance. RFC7432 describes four types of route to be exchanged through EVPN, with a built-in multihoming mechanism for redundancy. Prior to EOS 4.22.0F, MLAG was available as a redundancy option for EVPN with VXLAN, but not multihoming. EVPN multihoming is a multi-vendor standards-based redundancy solution that does not require a dedicated peer link and allows for more flexible configurations than MLAG, supporting peering on a per interface level rather than a per device level. It also supports a mass withdrawal mechanism to minimize traffic loss when a link goes down.

EVPN gateway support for all-active (A-A) multihoming adds a new redundancy model to our multi-domain EVPN solution introduced in [1]. This deployment model introduces the concept of a WAN Interconnect Ethernet Segment identifier (WAN I-ESI). The WAN I-ESI allows the gateway’s EVPN neighbors to form L2 and L3 overlay ECMP on routes re-exported by the gateways. The identifier is shared by gateway nodes within the same domain (site) and set in MAC-IP routes that cross domain boundaries.

This feature enables support for an EVPN VxLAN control plane in conjunction with Arista’s OpenStack ML2 plugin for

Starting with EOS release 4.22.0F, the EVPN VXLAN L3 Gateway using EVPN IRB supports routing traffic from one IPV6

Starting with EOS release 4.22.0F, the EVPN VXLAN L3 Gateway using EVPN IRB supports routing traffic from IPV6 host to

Starting with EOS release 4.22.0F, the EVPN VXLAN L3 Gateway using EVPN IRB supports routing traffic from one IPV6

In a traditional EVPN VXLAN centralized anycast gateway deployment, multiple L3 VTEPs serve the role of the

Typical WiFi networks utilize a single, central Wireless LAN Controller (WLC) to act as a gateway between the wireless APs and the wired network. Arista differentiates itself by allowing the wireless network to utilize a distributed set of aggregation switches to connect APs to the wired network. This feature allows a decentralized and distributed set of aggregation switches to bridge wireless traffic on behalf of the set of APs configured to VXLAN tunnel all traffic to those aggregation switches, or their “local” APs.

Disabling the flooding of broadcast, multicast, and unknown unicast traffic into the VXLAN fabric can significantly reduce bandwidth consumption in the VXLAN underlay. This is particularly beneficial in use cases where such traffic is unnecessary. This feature, exclusively supported with EVPN, allows for the selective flooding of ARP and/or ND traffic, offering further control over bandwidth usage.

In EVPN deployment with VXLAN underlay when an EVPN type 5 prefix is imported into an IP VRF, the IGP cost of the underlay

This solution allows delivery of IPv6 multicast traffic in an IP-VRF using an IPv4 multicast in the underlay network. The protocol used to build multicast trees in the underlay network is PIM Sparse Mode.

This solution allows delivery of both IPv4 and IPv6 multicast traffic in an IP-VRF using an IPv6 multicast in the underlay network. The protocol used to build multicast trees in the underlay network is IPv6 PIM-SSM.

Several customers have expressed interest in using IPv6 addresses for VXLAN underlay in their Data Centers (DC). Prior to 4.24.1F, EOS only supported IPv4 addresses for VXLAN underlay, i.e., VTEPs were reachable via IPv4 addresses only.

As of EOS 4.22.0F, EVPN all active multihoming is supported as a standardized redundancy solution. For effective

Ethernet VPN (EVPN) is an extension of the BGP protocol introducing a new address family: L2VPN (address family number 25) / EVPN (subsequent address family number 70). It is used to exchange overlay MAC and IP address reachability information between BGP peers using type-2 routes, but additionally,  EVPN supports the exchange of layer 3 IPv4 and IPv6 overlay routes through the extensions described in (type 5 EVPN routes).

This solution allows the delivery of customer BUM (Broadcast, Unknown unicast and Multicast) traffic in a VLAN using