Mobile User and Remote Network Routing to Service Connections
Table of Contents
Mobile User and Remote Network Routing to Service Connections
Learn how mobile user and remote network routing works
from Prisma Access service connections.
It is useful to understand how Prisma Access routes
traffic between mobile users, remote networks, and service connections,
because the routing used by mobile user traffic and remote network traffic
between service connections is different.
Mobile User-service connection routing—The mobile user
connection forms an IPSec tunnel with the nearest service connection.
Prisma Access uses iBGP for internal routing and eBGP to peer with
the customer premises equipment at the data center. The following
diagram shows mobile users in Regions 1 and 2 being routed to the
respective service connections in that region. Mobile users in Region
1 are accessing applications A and B located at Data
Center 1. If your organization’s network uses BGP routing for their
service connections and a service connection experiences an ISP
failure at Data Center 1, Prisma Access detects the failure and
routes the traffic for applications A and B to Data
Center 2 after BGP convergence, providing redundancy to your network’s
data centers.
Prisma Access uses the following timing with BGP when it
detects a failure: If you configure BGP routing and have enabled
tunnel monitoring, the shortest default hold time to determine that
a security parameter index (SPI) is failing is the tunnel monitor,
which removes all routes to a peer when it detects a tunnel failure
for 15 consecutive seconds. In this way, the tunnel monitor determines the
behavior of the BGP routes. If you do not configure tunnel monitoring,
the hold timer determines the amount of time that the tunnel is
down before removing the route. Prisma Access uses the default BGP HoldTime
value of 90 seconds as defined by RFC 4271, which is the maximum
wait time before Prisma Access removes a route for an inactive SPI.
If the peer BGP device has a shorter configured hold time, the BGP
hold timer uses the lower value. When the secondary tunnel is successfully
installed, the secondary route takes precedence until the primary
tunnel comes back up. If the primary and secondary are both up,
the primary route takes priority.
Remote Network-service connection routing—Prisma Access
creates a full mesh network with other remote networks and service
connections. As with mobile users, Prisma Access uses iBGP for its
internal routing and eBGP to peer with customer premises equipment
to exchange routes. If a user in Branch 1 is accessing application A from
Data Center 1 in your organization’s data center and the link between
Branch 1 and Data Center 1 goes down, Prisma Access routes the traffic
for application A to Data Center 2 after BGP convergence.
