Routing Policy
This section details Junos software routing policy operation and
configuration. The actual application of policy to solve some specific
networking requirement is generally left to the protocol-specific coverage
found in subsequent chapters. You configure policy-related options and statements at the
[edit policy-options]
hierarchy.
Routing policy and firewall filters have a similar syntax in Junos
software. The former deals with routes in the control plane, whereas the
latter deals with packets in the data plane. Firewalls are covered in
detail in a later chapter.
What Is a Routing Policy, and When Do I Need One?
Simply put, routing policy is used to:
Control what routes are installed into the route table for possible selection as an active route
Control what routes are exported from the route table, and into which protocols
Alter attributes of routes, either at reception or at the time of advertisement to other peers
Given that routing policy is used to control the reception and transmission of routing information and to alter route attributes, it’s safe to say that you need routing policy when the default policy does not meet your requirements.
The specifics of the various default policies are covered later, but to provide an example, consider that, by default, directly connected routes are not advertised into any routing protocol; in the case of RIP, not even when RIP is configured to run on those directly connected interfaces. If your goal is to get direct routes advertised ...
Get Junos Enterprise Routing, 2nd Edition now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.