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Cisco UC: SIP and TranslatorX

I can’t say how many times I had to configure SIP on Cisco voice gateways, troubleshoot SIP, enable SIP, etc. The second problem, after fear of loading and stuck the router using the “debug ccsip messages” command, is to filter and find the call in debugging turned on. If there is a way to collect all sip logs from the console...

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A little more Ansible

Templates There is a way to run playbook locally on the PC (generating some files, scripts or configs) using templates. Let’s say there is a template file (switch_template.j2): hostname {{ item.hostname }} ! interface loopback 0 ip address {{ item.loopback }} ! router eigrp 100 As a result of this playbook, 2 files will be generated: R1.txt and R2.txt Conditions Using...

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Ansible with Cisco

Documentation A good point to start – Ansible User Guide. Network modules (ios/nxos/ios-xr, aci, junos etc) – Module Index – Network Modules IOS/NXOS Command Modules IOS NXOS IOS There is are a way to run multiple commands Very useful for debugging to show output in the terminal: – name: show output     debug:          var: output Some...

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Ansible Intro

Automation is everywhere. I decided to take a quick look into Ansible Ansible is the simplest way to automate apps and IT infrastructure using SSH, with no agents to install on remote systems. Here is Intro to Ansible. Ansible – Open Source IT Automation Platform Notes: using SSH and does not require an agent written in Python push-based architecture Ansible Components...

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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...