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CCNP DC · vPC Lab 116

Nexus: build a vPC domain to an access switch

SW3 already bundles its two uplinks into Port-channel10 with LACP, one to N1 and one to N2. Without vPC that bundle cannot form across two switches. Turn N1 and N2 into a vPC pair so SW3 sees one partner and forwards on both links.

CCNP Data Center · Cisco Nexus (NX-OS-style) + Cisco · 6 objectives
CCNP DC · vPC FAILURE Lab 117

Nexus: vPC peer-link failure and orphan ports

The vPC domain is up: N1 is primary, N2 secondary, and SW3 forwards on both uplinks. PC3 hangs off N1 and PC2 off N2 on single, non-vPC ports. Break the peer-link and watch what each switch does while the keepalive is still alive.

CCNP Data Center · Cisco Nexus (NX-OS-style) + Cisco · 4 objectives
CCNP DC · vPC TROUBLESHOOTING Lab 118

Troubleshoot: vPC type-1 consistency failure

The vPC domain is formed, but vPC 10 is only half working: SW3 bundles just one uplink, so all its traffic squeezes through N1. Find the mismatch with the consistency checker and fix it.

CCNP Data Center · Cisco Nexus (NX-OS-style) + Cisco · 4 objectives
CCNP DC · vPC TROUBLESHOOTING Lab 119

Troubleshoot: the vPC peers never pair

N1 and N2 have a vPC domain, a working peer-link and vPC 10, yet show vpc says the peer adjacency is not formed and SW3 bundles neither uplink. The keepalive is cabled on Ethernet1/8 and both ends have addresses. Find out why the peers cannot hear each other, and fix it without moving the cable.

CCNP Data Center · Cisco Nexus (NX-OS-style) + Cisco · 4 objectives
CCNP DC · vPC TROUBLESHOOTING Lab 120

Troubleshoot: a vPC global type-1 mismatch

The vPC domain is formed, but vPC 10 is suspended on N2 and SW3 bundles only its N1 uplink. Every per-vPC parameter matches. Look at the parameters the two peers must share for the whole domain.

CCNP Data Center · Cisco Nexus (NX-OS-style) + Cisco · 4 objectives
CCNP DC · vPC Lab 121

Nexus: vPC peer-switch, one spanning-tree root

The vPC pair works, but each peer is still its own spanning-tree bridge: whichever wins is the root, and if it fails SW3 has to elect a new one. With peer-switch both peers send the same bridge ID, so the pair itself is the root and losing a peer changes nothing for spanning tree.

CCNP Data Center · Cisco Nexus (NX-OS-style) + Cisco · 4 objectives
CCNP DC · vPC TROUBLESHOOTING Lab 122

Troubleshoot: vPC peer-gateway and the router MAC

N1 (192.168.10.2, 192.168.20.2) and N2 (.3) route between VLAN 10 and VLAN 20 with plain SVIs, no HSRP. PC1 uses N2’s own address 192.168.10.3 as its gateway. PC1 and PC4 sit behind the same vPC on SW3, yet PC1 cannot reach PC4 (192.168.20.40). Find out why, and fix it in the vPC domain.

CCNP Data Center · Cisco Nexus (NX-OS-style) + Cisco · 4 objectives
CCNP DC · OTV Lab 123

Nexus: OTV unicast-only with an adjacency server

Two data centers both use VLAN 10 (192.168.10.0/24), but they are joined only by a routed core. Extend VLAN 10 between them with OTV in unicast-only mode, so PCA reaches PCB at Layer 2 while spanning tree stays inside each site.

CCNP Data Center · Cisco Nexus (NX-OS-style) + Cisco · 5 objectives
CCNP DC · OTV MULTICAST Lab 124

Nexus: OTV over a multicast core

The core router already runs PIM sparse mode with 3.3.3.3 as the RP. Use it as the OTV control plane: the edges find each other through a shared control group instead of an adjacency server.

CCNP Data Center · Cisco Nexus (NX-OS-style) + Cisco · 5 objectives
CCNP DC · OTV TROUBLESHOOTING Lab 125

Troubleshoot: OTV site identifier

OTV is configured on both data centers and the overlay adjacency is up, yet PCA cannot reach PCB. Find out why the edges refuse to extend VLAN 10 to each other and fix it.

CCNP Data Center · Cisco Nexus (NX-OS-style) + Cisco · 4 objectives
CCNP DC · FABRICPATH Lab 126

Nexus: a FabricPath spine-leaf fabric

Two spines and two leaves are cabled as a full mesh. With classic spanning tree half of those links would be blocked. Build a FabricPath fabric instead: every link forwards, and each leaf reaches the other over both spines.

CCNP Data Center · Cisco Nexus (NX-OS-style) · 5 objectives
CCNP DC · FABRICPATH EDGE Lab 127

Nexus: FabricPath edge toward classic Ethernet

SW3 is a classic Ethernet switch with one uplink to each leaf. The FabricPath edge switches act as one spanning-tree bridge (c84c.75fa.6000) toward it, but SW3 currently has the better bridge ID, so the leaves block their edge ports and PC3 is cut off. Make the fabric the root.

CCNP Data Center · Cisco Nexus (NX-OS-style) + Cisco · 4 objectives
CCNP DC · vPC+ Lab 128

Nexus: vPC+ on a FabricPath edge

SW3 bundles its two uplinks into Port-channel20 with LACP, one to each leaf. Inside a FabricPath fabric the leaves pair up with vPC+: a vPC domain whose peer-link is a FabricPath port and which is known to the rest of the fabric as one emulated switch-id.

CCNP Data Center · Cisco Nexus (NX-OS-style) + Cisco · 6 objectives
CCNP DC · FABRICPATH TROUBLESHOOTING Lab 129

Troubleshoot: FabricPath switch-id and VLAN mode

The fabric is cabled and FabricPath is enabled everywhere, yet PC1 cannot reach PC2. There are two faults. Find them with the FabricPath show commands and fix them.

CCNP Data Center · Cisco Nexus (NX-OS-style) · 4 objectives
CCNP DC · VXLAN Lab 130

Nexus: VXLAN flood-and-learn with static ingress replication

L1 and L2 are leaves joined only by a routed underlay (OSPF through S1). Both have hosts in VLAN 10. Stretch VLAN 10 across the underlay with VXLAN: map it to VNI 10010 and replicate broadcast and unknown traffic to the other VTEP by unicast.

CCNP Data Center · Cisco Nexus (NX-OS-style) · 5 objectives
CCNP DC · VXLAN MULTICAST Lab 131

Nexus: VXLAN over a multicast underlay

The underlay already runs PIM sparse mode on every link and loopback, with S1 (3.3.3.3) as the RP. Let the underlay replicate VNI 10010’s broadcast and unknown traffic: both leaves join one multicast group for the VNI.

CCNP Data Center · Cisco Nexus (NX-OS-style) · 4 objectives
CCNP DC · BGP EVPN Lab 132

Nexus: BGP EVPN control plane for VXLAN

Replace flood-and-learn with a control plane. S1 becomes an iBGP route reflector for the L2VPN EVPN address family; each leaf advertises its VNI (a type-3 route) and its hosts (type-2 routes), and the leaves find each other from those routes.

CCNP Data Center · Cisco Nexus (NX-OS-style) · 5 objectives
CCNP DC · EVPN TROUBLESHOOTING Lab 133

Troubleshoot: BGP EVPN route-targets

BGP EVPN is configured on the fabric and every BGP session is up, but the leaves do not list each other as NVE peers and PC1 cannot reach PC2. There are two faults, one on each leaf.

CCNP Data Center · Cisco Nexus (NX-OS-style) · 4 objectives
CCNP DC · EVPN L3 (SYMMETRIC IRB) Lab 134

Nexus: EVPN Layer 3 with an anycast gateway

The BGP EVPN fabric carries VLAN 10 (VNI 10010) on L1 and VLAN 20 (VNI 10020) on L2, but nothing routes between them. Add a tenant VRF with a Layer 3 VNI: each leaf is the anycast gateway of its subnet, and traffic between subnets is routed into VNI 50000, carried to the other leaf and routed again there (symmetric IRB).

CCNP Data Center · Cisco Nexus (NX-OS-style) · 6 objectives
CCNP DC · EVPN TYPE-5 Lab 135

Nexus: EVPN type-5 prefix routes from a border leaf

L2 is also the border leaf: in VRF TENANT it reaches an outside network, stood in for by loopback100 (10.100.100.0/24). Hosts have type-2 routes, but a whole prefix needs a type-5 (IP prefix) route. Advertise it into EVPN.

CCNP Data Center · Cisco Nexus (NX-OS-style) · 4 objectives
CCNP DC · EVPN L3 TROUBLESHOOTING Lab 136

Troubleshoot: the EVPN Layer 3 VNI

The tenant VRF is configured on both leaves and each host reaches its own gateway, yet PC1 cannot reach PC2 in the other subnet. One piece of the Layer 3 VNI is missing on each leaf.

CCNP Data Center · Cisco Nexus (NX-OS-style) · 4 objectives