Cisco Live 2019 Break Down Session SD-Access1, Slides of Computer Networks

Download Cisco Live 2019 Break Down Session SD-Access1 and more Slides Computer Networks in PDF only on Docsity!

Michel Peters,

Technical Leader Engineering

BRKARC- 2020

SD Access:

Troubleshooting the fabric

Fabric

The basic fabric Edge Edge CP (^) Border Underlay

Connection to outside

Endpoint connectivity

Control Plane

5

SD Access Fabric Key Technologies

• Locator/ID Separation Protocol, Control plane protocol inside the fabric
• Cisco TrustSec, Allows traffic policies to be deployed and enforced inside the fabric
• Authentication, Assigns endpoints using Dot1x/MAB with their respective authentication parameters and VN
• VXLAN, Dataplane protocol. Encapsulates traffic inside the Fabric

LISP Basic operation

• LISP is a routing architecture.
• LISP creates a level of indirection by using two spaces: “locators” (RLOC) and “endpoints” (EID)
• Advertise “locators” in core routing. Removes “hosts” from routing tables. Host prefixes moved to an alternative system database
• Routers in Underlay only need routing information to RLOC space, simplifies Underlay network
• To get path information to end hosts, routers query locator-end host map servers. Mapping analogous to DNS.
• Routers hold map-cache of locator-hosts.

Mappings

Cisco DNA Center Switch Side LISP

Virtual network (VN) VRF Instance ID

Underlay Network Global Routing Table Global Routing Table

IP Pool Vlan/SVI with IP Subnet EID space

Default Gateway of Pool Anycast IP address -

Scalable Groups Secure Group Tag Policy Label in vxlan

Policy Contract SGACL -

10

LISP basic operation, registering with CP Edge Edge CP (^) Border

• Edge detect IP Address of Endpoint in Dynamic EID space
• Edge registers Endpoint IP with CP
• CP maintains database with EID to RLOC information /32 for Endpoints , subnets from Borders RLOC EID Edge_1 192.168.100. Edge_2 192.168.100. Underlay 11

LISP basic operation, packet forwarding Edge Edge CP (^) Border

• Edge_1 encapsulates packet in vxlan and sends it to RLOC of edge_
• Edge_2 de-encapsulates packet and forwards to endpoint 2 RLOC EID Edge_1 192.168.100. Edge_2 192.168.100. Underlay 13

ORIGINAL ETHERNET IP PAYLOAD PACKET PACKET IN IP UDP LISP IP PAYLOAD LISP ETHERNET ETHERNET IP UDP VXLAN ETHERNET IP PAYLOAD PACKET IN VXLAN Supports L & L3 Overlay Supports L Overlay

• Packets inside an SDA Fabric are encapsulated in VXLAN
• Full packet encapsulated , Mac and IP Layers
• VXLAN uses UDP Destination port Data Plane

Layer 3 Forwarding

Layer 3 in the Fabric Edge Edge CP (^) Border

• Traffic inside Fabric encapsulated in VXLAN
• Traffic in Virtual Networks(VN) send from RLOC to RLOC using Layer 3 LISP instance
• EID space configured as Dynamic EID
• Borders are egress points out of fabric
• Edges setup with VRF per VN and SVI ‘s
• Edges and Fabric register EID with Control Plane. RLOC EID Edge_1 192.168.100. Edge_2 192.168.100. Border1 172.16.100/ Underlay 17

Registration of Endpoints with CP node

• Endpoints can be reached when learned by Edge and registered with CP
• Dynamic Endpoints learned via ARP (Layer 3) and Device Tracking (layer 2/3)
• IP address of endpoint gets signaled to LISP process who registers the IP address with the Control Plane node using map-register

Locally Registered Endpoints

192.168.100.99/32 shown as

reachable, Locator is Lo0 of switch

• Solicited Map Request Table shows local EID for active entries.
• Aged out entries show as Away 20