Routing

Hi all,

 

I am trying to install a generated route using a policy referencing a direct link to an eBGP neigbor using vSRX.

 

R9 <<< ----- >>> R8

 

The basic configuration is:

 

Default generated route

==================

 

route 0.0.0.0/0 policy generated-route-default;

 

Policy

=====

term 1 {
    from {
        protocol local;
        route-filter 84.10.113.0/30 exact;
    }
    then accept;
}
term 2 {
    then reject;
}

 

 

Routing details

============

 

root@R8> show route protocol aggregate 0/0 hidden detail

inet.0: 29 destinations, 39 routes (28 active, 0 holddown, 1 hidden)
0.0.0.0/0 (1 entry, 0 announced)
         Aggregate
                Next hop type: Reject
                Address: 0x8f3d584
                Next-hop reference count: 3
                State: <Hidden Int Ext>
                Local AS:  1282
                Age: 38:54
                Task: Aggregate
                AS path: I
                                Flags: Generate    Depth: 1    Inactive
root@R8> show route 84.10.113.0/30

inet.0: 29 destinations, 39 routes (28 active, 0 holddown, 1 hidden)
+ = Active Route, - = Last Active, * = Both

84.10.113.0/30     *[Direct/0] 01:34:14
                    > via ge-0/0/7.0
84.10.113.1/32     *[Local/0] 01:34:14
                      Local via ge-0/0/7.0

 

Version

======

 

Model: firefly-perimeter
JUNOS Software Release [12.1X47-D20.7]

 

Im probably missing something obvious here 🙂 but a nudge in the right direction would be appreciated 🙂

 

Apologies in advance if the etiquete and formatting arent on point....this is my first tech post on the forums 😉

try to change from protocol local to protocol direct 

or 

change "route-filter 84.10.113.0/30 exact" to "route-filter 84.10.113.1/32 exact"

 

compare your output of "show route " and configuration of policy

Hi Akushner,

 

Thanks for the reply. I have tried both of those and still no luck.

Martin

Hi, 
 
Direct routes for multiaccess networks cannot contribute to a generated route because a forwarding next hop cannot be derived from the mere presence of the local interface, as is possible in the case of a point-to-point link, where the interface itself can be specified as a next hop.

Junos Enterprise Routing: A Practical Guide to Junos Routing and Certification, page 126

Hi Doods thanks for the information.

Reference: Junos Enterprise Routing: A Practical Guide to Junos Routing and Certification, page 126

Hi Doods,

 

thanks for the pointer on the book and page reference. However on page 271 am I misreading that its a direct route conributing to the generated route on this:

 

[edit]
lab@Yeast# show routing-options generate
route 0.0.0.0/0 policy gen_default;
[edit]
lab@Yeast# show policy-options policy-statement gen_default
term 1 {
from {
protocol direct;
route-filter 84.10.113.0/31 exact;
}
then accept;
}
term 2 {
then reject;
}
The configuration results in the generation of a 0/0 route that, when matched, will
forward over the next hop assigned to the preferred contributing route. Here, the set
of possible contributors is constrained by the policy named gen_default, which matches
only on the 84.10.113.0/31 route assigned to the t1-2/0/2 interface. The policy’s second term guarantees that no other route can contribute by rejecting all remaining routes
and sources. Operation of the generated route is verified:
[edit]
lab@Yeast# run show route protocol aggregate detail
inet.0: 17 destinations, 17 routes (17 active, 0 holddown, 0 hidden)
0.0.0.0/0 (1 entry, 1 announced)
*Aggregate Preference: 130
Next-hop reference count: 2
Next hop: via t1-2/0/2.0, selected
State: <Active Int Ext>
Age: 10:07
Task: Aggregate
Announcement bits (1): 0-KRT
AS path: I
Flags: Generate Depth: 0 Active
Contributing Routes (1):
84.10.113.0/31 proto Direct

Hi, 

 

Yes beceause it is a point to point interface. (/31).

Great thanks 🙂

I still seem unable to get the Generated route to recognise the contributing route and install  0/0 into the route table?

 

set interfaces ge-0/0/1 description "toR9-BGP Link to AS34"
set interfaces ge-0/0/1 unit 0 family inet address 84.10.109.0/31

 

set policy-options policy-statement generate term 1 from protocol direct
set policy-options policy-statement generate term 1 from route-filter 84.10.109.0/31 exact
set policy-options policy-statement generate term 1 then accept
set policy-options policy-statement generate term 2 then reject

 

set routing-options generate route 0.0.0.0/0 policy generate

 

root@R8# run show route protocol aggregate hidden detail

inet.0: 18 destinations, 18 routes (17 active, 0 holddown, 1 hidden)
0.0.0.0/0 (1 entry, 0 announced)
Aggregate
Next hop type: Reject
Address: 0x8f3d584
Next-hop reference count: 1
State: <Hidden Int Ext>
Local AS: 1282
Age: 17:50
Task: Aggregate
AS path: I
Flags: Generate Depth: 0 Inactive

 

 

root@R8# run show route | match 84     
84.10.109.0/31     *[Direct/0] 00:35:58 >>>>>>>>> ge-0/0/1
84.10.109.0/32     *[Local/0] 00:35:58
84.10.113.0/30     *[Direct/0] 00:35:58
84.10.113.1/32     *[Local/0] 00:35:58

 

root@R8# run show route 84.10.109.0/31 detail

inet.0: 18 destinations, 18 routes (17 active, 0 holddown, 1 hidden)
84.10.109.0/31 (1 entry, 0 announced)
        *Direct Preference: 0
                Next hop type: Interface
                Address: 0x9350208
                Next-hop reference count: 1
                Next hop: via ge-0/0/1.0, selected
                State: <Active Int>
                Local AS:  1282
                Age: 36:49
                Task: IF
                AS path: I

84.10.109.0/32 (1 entry, 0 announced)
        *Local  Preference: 0
                Next hop type: Local
                Address: 0x8f3ede4
                Next-hop reference count: 5
                Next hop:
                Interface: ge-0/0/1.0
                State: <Active NoReadvrt Int>
                Local AS:  1282
                Age: 36:49              
                Task: IF
                AS path: I

 

oot@R8# run show route

inet.0: 18 destinations, 18 routes (17 active, 0 holddown, 1 hidden)
+ = Active Route, - = Last Active, * = Both

10.10.10.5/32      *[OSPF/10] 00:37:56, metric 2
                    > to 192.168.0.2 via ge-0/0/6.0
10.10.10.6/32      *[OSPF/10] 00:37:56, metric 2
                    > to 192.168.0.2 via ge-0/0/6.0
10.10.10.7/32      *[OSPF/10] 00:37:56, metric 1
                    > to 192.168.0.2 via ge-0/0/6.0
10.10.10.8/32      *[Direct/0] 00:38:11
                    > via lo0.0
84.10.109.0/31     *[Direct/0] 00:38:11
                    > via ge-0/0/1.0
84.10.109.0/32     *[Local/0] 00:38:11
                      Local via ge-0/0/1.0
84.10.113.0/30     *[Direct/0] 00:38:11
                    > via ge-0/0/7.0
84.10.113.1/32     *[Local/0] 00:38:11
                      Local via ge-0/0/7.0
192.168.0.0/30     *[Direct/0] 00:38:11
                    > via ge-0/0/6.0
192.168.0.1/32     *[Local/0] 00:38:11
                      Local via ge-0/0/6.0
192.168.1.0/30     *[OSPF/10] 00:37:56, metric 2
                    > to 192.168.0.2 via ge-0/0/6.0
192.168.2.0/30     *[OSPF/10] 00:37:56, metric 2
                    > to 192.168.0.2 via ge-0/0/6.0
192.168.3.0/30     *[OSPF/10] 00:37:56, metric 3
                    > to 192.168.0.2 via ge-0/0/6.0
192.168.4.0/30     *[OSPF/10] 00:37:56, metric 3
                    > to 192.168.0.2 via ge-0/0/6.0
192.168.5.0/30     *[OSPF/10] 00:37:56, metric 4
                    > to 192.168.0.2 via ge-0/0/6.0
192.168.6.0/30     *[OSPF/10] 00:37:56, metric 3
                    > to 192.168.0.2 via ge-0/0/6.0
224.0.0.5/32       *[OSPF/10] 00:38:11, metric 1
                      MultiRecv

Hello,

If Your goal is to send everything into ge-0/0/1 when it is up/up, then You won't be able to do it with generate route. Static 0/0 with next-hop 84.10.109.1 is the solution.

If Your goal is to announce 0/0 route when ge-0/0/1 is up/up, then use "aggregate" route with discard NH, it will consider 84.10.109.0/31 as contributor.

 

JUNOS CLI:

 

 

set policy-options policy-statement generate term 1 from protocol direct
set policy-options policy-statement generate term 1 from route-filter 84.10.109.0/31 exact
set policy-options policy-statement generate term 1 then accept
set policy-options policy-statement generate term 2 then reject
 
set routing-options aggregate route 0.0.0.0/0 policy generate
set routing-options aggregate route 0.0.0.0/0 discard ## not strictly necessary but stops wasteful ICMP Unreach generation

And then match appropriately in Your IGP/BGP export policies.

HTH

Thx
Alex

Hi,

 

Apologies for the delayed reply 🙂 I'll try this later on and let you know how I get on.

 

Thanks

Is it working for the book example because they're using a t1 interface and that's not considered a mulitaccess interface?

inet.0: 29 destinations, 39 routes (28 active, 0 holddown, 1 hidden)
+ = Active Route, - = Last Active, * = Both

84.10.113.0/30 *[Direct/0] 01:34:14
> via ge-0/0/7.0
84.10.113.1/32 *[Local/0] 01:34:14
Local via ge-0/0/


First thing to understand is that as you are using and statement in term 1 from local and exact .
So make it as from direct

As routing table shows in hidden routes , we cannot send