Routing

Hi everybody,

I am newer in JunOS, althought I know Cisco IOS I don't understand why my BGP configuration doesn't advertise the routes. Could you help me?

root@B1> show configuration routing-options                                  
graceful-restart;
static {
    route 1.2.104.0/26 discard;
    route 1.2.104.128/25 discard;
    route 0.0.0.0/0 discard;
}
aggregate {
    route 1.2.104.0/26;
    route 1.2.104.128/25;
}
router-id 10.16.254.1;
autonomous-system 64;
forwarding-table {
    export load-balacing;
}

root@B1> show configuration protocols bgp group R64              
type external;
family inet {
    unicast;
}
export [ RB ];
peer-as 7;
local-as 64;
neighbor 13.20.19.5 {
    description "PEERING A RS";
    preference 160;
    local-address 13.20.19.6;
}

root@B1> show configuration policy-options policy-statement RB   
from {
    protocol aggregate;
    route-filter 1.2.104.0/26 exact;
    route-filter 1.2.104.128/25 exact;
}
then accept;

root@B1> show route advertising-protocol bgp 13.20.19.5 all              

inet.0: 23 destinations, 25 routes (22 active, 0 holddown, 2 hidden)
Restart Complete
  Prefix                  Nexthop              MED     Lclpref    AS path

Thanks a lot, best regards.

hi,

In your setup both aggregate are hidden (show route hidden extensive).

http://www.juniper.net/techpubs/en_US/junos/topics/topic-map/policy-aggregate-route.html says:

An aggregate route becomes active when it has one or more contributing routes. A contributing route is an active route that is a more specific match for the aggregate destination

you don't need aggregate if it's the same as static route. Export static routes or change the contributing static routes to be more specific then aggregates.

jtb 

Thanks a lot jtb,

Exactly, there are hidden aggregates, what does it mean?

root@B1> show route hidden extensive

1.2.104.128/25 (1 entry, 0 announced)
         Aggregate
                Next hop type: Reject
                Address: 0x8f27f24
                Next-hop reference count: 5
                State: <Hidden Int Ext>
                Local AS: 64
                Age: 2d 22:50:03
                Task: Aggregate
                AS path: I
                                Flags: ASPathChanged    Depth: 0        Inactive

However, if I run:

 # delete routing-options static route 1.2.104.0/26 discard

 # delete routing-options static route 1.2.104.128/25 discard

 # commit

The router advertise 1.2.104.0/26 but not 1.2.104.128/25. I think it is because the router has a network interface with the address 1.2.104.1/28. 

With regards to 1.2.104.128/25, how can I change the contributing static routes to be more specific?

Thanks, best regards.

hi,

> Exactly, there are hidden aggregates, what does it mean?

http://www.juniper.net/techpubs/en_US/junos/topics/concept/hidden-routes-understanding.html says:

Hidden routes are routes that the device cannot use for reasons such as an invalid next hop or a routing policy that rejects the routes.

In your case to make aggregates active, Junos requires to have active contributing routes (more specific routes). For 1.2.104.0/26 it may any subnet of the prefix, like 1.2.104.0/27, 1.2.104.1/32, etc.

The router needs to have a route to any subnet 'covered' by the aggregate. It must be more specific (smaller net) then the aggregate - your static routes are the same as aggregates.

Let's test the config.

1)  Just aggregates, no contributing routes. The aggregates are hidden (non usable):

admin@Junos# show routing-options
aggregate {
    route 1.2.104.0/26;
    route 1.2.104.128/25;
}

admin@Junos# run show route 1.2.104.0/26

inet.0: 4 destinations, 4 routes (2 active, 0 holddown, 2 hidden)

[edit]
admin@Junos# run show route 1.2.104.128/25 

inet.0: 4 destinations, 4 routes (2 active, 0 holddown, 2 hidden)

admin@Junos# run show route hidden detail

inet.0: 4 destinations, 4 routes (2 active, 0 holddown, 2 hidden)
1.2.104.0/26 (1 entry, 0 announced)
         Aggregate
                Next hop type: Reject
                Address: 0x24dfbd4
                Next-hop reference count: 2
                State: <Hidden Int Ext>
                Age: 1:03
                Validation State: unverified
                Task: Aggregate
                AS path: I
                Flags:                  Depth: 0        Inactive

1.2.104.128/25 (1 entry, 0 announced)
         Aggregate
                Next hop type: Reject
                Address: 0x24dfbd4
                Next-hop reference count: 2
                State: <Hidden Int Ext>
                Age: 1:03
                Validation State: unverified
                Task: Aggregate
                AS path: I
                Flags:                  Depth: 0        Inactive

[edit]
admin@Junos#

2)  Let's add your static routes - equal to aggregates (not valid contributing routes).

      Static routes are active (and can be exported in BGP policy)

      Aggregates are hidden (can't be exported)

admin@Junos# show routing-options
static {
    route 1.2.104.0/26 discard;
    route 1.2.104.128/25 discard;
}
aggregate {
    route 1.2.104.0/26;
    route 1.2.104.128/25;
}

[edit]
admin@Junos# run show route 1.2.104.0/26 exact 

inet.0: 4 destinations, 6 routes (4 active, 0 holddown, 2 hidden)
+ = Active Route, - = Last Active, * = Both

1.2.104.0/26       *[Static/5] 00:01:47
                      Discard

[edit]
admin@Junos# run show route 1.2.104.128/25 exact 

inet.0: 4 destinations, 6 routes (4 active, 0 holddown, 2 hidden)
+ = Active Route, - = Last Active, * = Both

1.2.104.128/25     *[Static/5] 00:01:56
                      Discard

[edit]
admin@Junos# 

admin@Junos# run show route 1.2.104.0/26 exact all

inet.0: 4 destinations, 6 routes (4 active, 0 holddown, 2 hidden)
+ = Active Route, - = Last Active, * = Both

1.2.104.0/26       *[Static/5] 00:02:19
                      Discard
                    [Aggregate] 00:00:45
                      Reject

[edit]
admin@Junos# run show route 1.2.104.128/25 exact all  

inet.0: 4 destinations, 6 routes (4 active, 0 holddown, 2 hidden)
+ = Active Route, - = Last Active, * = Both

1.2.104.128/25     *[Static/5] 00:02:25
                      Discard
                    [Aggregate] 00:00:51
                      Reject

[edit]
admin@Junos# 

admin@Junos# run show route protocol aggregate 1.2.104.0/26 all detail

inet.0: 4 destinations, 6 routes (4 active, 0 holddown, 2 hidden)
1.2.104.0/26 (2 entries, 1 announced)
         Aggregate
                Next hop type: Reject
                Address: 0x24dfbd4
                Next-hop reference count: 2
                State: <Hidden Int Ext>
                Inactive reason: Unusable path
                Age: 1:24 
                Validation State: unverified 
                Task: Aggregate
                AS path: I
                Flags:                  Depth: 0        Inactive

[edit]
admin@Junos# run show route protocol aggregate 1.2.104.128/25 all detail  

inet.0: 4 destinations, 6 routes (4 active, 0 holddown, 2 hidden)
1.2.104.128/25 (2 entries, 1 announced)
         Aggregate
                Next hop type: Reject
                Address: 0x24dfbd4
                Next-hop reference count: 2
                State: <Hidden Int Ext>
                Inactive reason: Unusable path
                Age: 1:41 
                Validation State: unverified 
                Task: Aggregate
                AS path: I
                Flags:                  Depth: 0        Inactive

[edit]
admin@Junos# 

3)  let's change the static routes to be more specific.

     Now aggregates are active as expected and will be exported by the BGP policy.

admin@Junos# show routing-options
static {
    route 1.2.104.0/30 discard;
    route 1.2.104.128/30 discard;
}
aggregate {
    route 1.2.104.0/26;
    route 1.2.104.128/25;
}


admin@Junos# run show route 1.2.104.0/26

inet.0: 6 destinations, 6 routes (6 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

1.2.104.0/26       *[Aggregate/130] 00:05:56
                      Reject
1.2.104.0/30       *[Static/5] 00:01:27
                      Discard

[edit]
admin@Junos# run show route 1.2.104.128/25               

inet.0: 6 destinations, 6 routes (6 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

1.2.104.128/25     *[Aggregate/130] 00:05:59
                      Reject
1.2.104.128/30     *[Static/5] 00:01:30
                      Discard
                      
admin@Junos# run show route 1.2.104.0/26 exact detail

inet.0: 6 destinations, 6 routes (6 active, 0 holddown, 0 hidden)
1.2.104.0/26 (1 entry, 1 announced)
        *Aggregate Preference: 130
                Next hop type: Reject
                Address: 0x24dfbd4
                Next-hop reference count: 4
                State: <Active Int Ext>
                Age: 6:17 
                Validation State: unverified 
                Task: Aggregate
                Announcement bits (1): 0-KRT 
                AS path: I (LocalAgg)
                Flags:                  Depth: 0        Active
                AS path list:
                AS path: I Refcount: 1
                Contributing Routes (1):
                        1.2.104.0/30 proto Static

[edit]
admin@Junos# run show route 1.2.104.128/25 exact detail

inet.0: 6 destinations, 6 routes (6 active, 0 holddown, 0 hidden)
1.2.104.128/25 (1 entry, 1 announced)
        *Aggregate Preference: 130
                Next hop type: Reject
                Address: 0x24dfbd4
                Next-hop reference count: 4
                State: <Active Int Ext>
                Age: 6:25 
                Validation State: unverified 
                Task: Aggregate
                Announcement bits (1): 0-KRT 
                AS path: I (LocalAgg)
                Flags:                  Depth: 0        Active
                AS path list:
                AS path: I Refcount: 1
                Contributing Routes (1):
                        1.2.104.128/30 proto Static

[edit]
admin@Junos#

> The router advertise 1.2.104.0/26 but not 1.2.104.128/25. I think it is because the router has a network interface with the address 1.2.104.1/28. 

correct

> With regards to 1.2.104.128/25, how can I change the contributing static routes to be more specific?

see example above, hope that helps.

Play with the config and verify results.

jtb

Thanks a lot jtb, your explanation is very clear.

It seems to work well and now I understand the issue.

Best regards.

Good to know. Now if you could mark jtb solution as solved, throw in kudos, we can all benefit from this and others who search the forum for answers can find this resolution also.