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Cisco NX-OS: VXLAN and External Connectivity

By default: underlay – default VRF overlay – “tenant” VRF, hosts in VXLAN are isolated Border Leafs are used to connect the internal fabric to external networks. Not necessary a box, just configuration on the Leaf. It maintains the following routing control planes: MP-BGP L2VPN EVPN – inside VXLAN fabric “tenant” VRF BGP or IGP to external routes MP-BGP to BGP/IGP...

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Cisco NX-OS: VXLAN – vPC – Anycast

VxLAN and vPC Anycast VTEP Problem with VXLAN and vPC: in a vPC both vPC peers duplicate EVPN MAC/IP routes to spine RRs with other attributes equal, one vPC peer is always preferred for dual attached hosts (based on the normal BGP Best path selection) Result: egress traffic from vPC Member is load-balanced, but return ingress traffic is polarized Solution: Anycast VTEP...

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Cisco NX-OS: VXLAN Symmetric Routing

EVPN Integrated Routing and Bridging (IRB) has two options: Asymmetric IRB (increased ARP cache and CAM table sizes and control plane scaling issue) Symmetric IRB Symmetric IRB Ingress VTEP does both L2 and L3 lookup Egress VTEp does both L3 and L2 lookup => Bridge – Route – Route – Bridge L3 VNI should be configured on all VTEPS, L2 VNIs...

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2019 IT Blog Awards by Cisco

Today I’ve received a badge from Cisco. I made the finalist for the IT Blog Awards 2019 by Cisco in the Best Newcomer category! Discover all the awesome podcasts and resources. There are a lot of great blogs out there. To vote click here. Best Analysis – Does this blog provide insightful discussions? Houman Asefi How Does Internet Work mrnCCIEW Network Defense...

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Cisco NX-OS: VXLAN Asymmetric Routing

EVPN Integrated Routing and Bridging (IRB) has two options: Asymmetric IRB Symmetric IRB Assymetric IRB Ingress VTEP does both L2 and L3 lookup Egress VTEP does L2 lookup only => Bridge – Route – Bridge Pros: “easy” to configure – just copy/paste. Identical config with the only difference in SVI IP addresses. Cons: on the way back, traffic will be reversed...

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Cisco NX-OS: VXLAN BGP EVPN control plane

Two control planes for the VXLAN technology: Multicast control plane (flood-and learn) MP-BGP EVPN control plane MP-BGP EVPN is a standard-based VXLAN control protocol, that provides remote VTEP discovery and MAC/ARP learning. Ethernet Virtual Private Network (EVPN) reduces flooding in the network and resolves scalability concerns. MP-BGP is used to exchange information between VTEPs Devices might be MP-iBGP EVPN peers or...

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Cisco NX-OS: VXLAN Multicast Control Plane

Two control planes for the VXLAN technology: Multicast control plane (flood and learn) MP-BGP EVPN control plane Virtual Extensible Local Area Networks (VXLANs) allows to extend reachability of a VLAN within a data center over Layer 3. Every VTEP with specific VXLAN and certain VNI will join the same multicast group. To learn remote MAC addresses, the VTEP will use conversational...

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Cisco NS-OS: Virtual eXtensible LAN (VXLAN) Overview

VXLAN is a tunneling protocol that encapsulates Layer 2 Ethernet frames in Layer 3 UDP packets. Why VXLAN: VLAN Scalability  – expands VLAN name space VLANs use 12 bit -4096 values VXLAN uses 24 bit – 16777216 values allows layer 2 multipathing no STP uses layer 3 ECMP over CLOS fabric (like FabricPath) allows for multi-tenancy separate of customer traffic over shared...

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Cisco UC: ISR box-to-box REDundancy

The Interchassis High Availability feature (box-to-box redundancy) enables the configuration of pairs of routers to act as backup for each other. Failover: the standby router seamlessly takes over and starts processing call signaling and performing media forwarding tasks. Note: failover causes reboot by design. Configuration on ISR 4000 series Enable CUBE and redundancy on both routers: Configure an redundancy group with...

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Cisco UC: PRTG and SIP calls

I found several ways monitoring SIP calls in PRTG using SNMP. Monitor active calls using SIP legs/2 Monitor each dial-peer separately and combine them in the Sensor Factory Just monitor multiple OIDs in one Sensor Enable SNMP on the CUBE: 1. Monitor active calls using SIP legs Idea: check how many SIP legs on the voice gateways (show call active voice...