Hello,
We are testing MPLS in our lab using two MX960s with a few LS to add more
routers. I'm using OSPF as the IGP and LDP for transport labels. We're on 10.0
code so I've been testing OSPF LFA. It appears to be doing something strange
and I can't tell if it's per design or a bug.
Here's a PE's route to a destination PE loopback:
----------------------
se36...@pe1-stjhlab-re0> show route 10.10.80.2 logical-system PE10 detail
inet.0: 34 destinations, 34 routes (34 active, 0 holddown, 0 hidden)
10.10.80.2/32 (1 entry, 1 announced)
*OSPF Preference: 10
Next hop type: Router, Next hop index: 1192
Next-hop reference count: 40
Next hop: 10.10.81.10 via xe-0/3/0.0, selected
State: <Active Int>
Local AS: 855
Age: 2 Metric: 2
Area: 0.0.0.0
Task: OSPF
Announcement bits (3): 2-LDP 3-KRT 5-Resolve tree 2
AS path: I
inet.3: 7 destinations, 7 routes (7 active, 0 holddown, 0 hidden)
10.10.80.2/32 (1 entry, 1 announced)
State: <FlashAll>
*LDP Preference: 9
Next hop type: Router
Next-hop reference count: 3
Next hop: 10.10.81.10 via xe-0/3/0.0, selected
Label operation: Push 299776
State: <Active Int>
Local AS: 855
Age: 2 Metric: 1
Task: LDP
Announcement bits (2): 2-Resolve tree 1 3-Resolve tree 2
AS path: I
{master}
se36...@pe1-stjhlab-re0> show ldp route logical-system PE10 10.10.80.2
extensive
Destination Next-hop intf/lsp Next-hop address
10.10.80.2/32 xe-0/3/0.0 10.10.81.10
Session ID 10.10.80.10:0--10.10.80.1:0
Bound to outgoing label 299840, Topology entry: 0x8e69980
Ingress route status: Active, Last modified: 00:00:10 ago
se36...@pe1-stjhlab-re0> traceroute 10.10.80.2 logical-system PE10 no-resolve
traceroute to 10.10.80.2 (10.10.80.2), 30 hops max, 40 byte packets
1 10.10.81.10 0.353 ms 0.274 ms 0.279 ms
2 10.10.80.2 0.460 ms 0.455 ms 0.437 ms
{master}
se36...@pe1-stjhlab-re0> traceroute mpls ldp 10.10.80.2 logical-system PE10
no-resolve
Probe options: ttl 64, retries 3, wait 10, paths 16, exp 7, fanout 16
ttl Label Protocol Address Previous Hop Probe Status
1 299776 LDP 10.10.81.10 (null) Success
2 3 LDP 10.10.81.1 10.10.81.10 Egress
Path 1 via xe-0/3/0.0 destination 127.0.0.64
----------------------
Everything is normal. IP packets are following the OSPF shortest path per the
costs I've set. The LDP LSP is following OSPF.
Now I turn on OSPF LFA "link-protection" on the links and re-run the same tests:
-----------------------
se36...@pe1-stjhlab-re0> show route 10.10.80.2 logical-system PE10 detail
inet.0: 34 destinations, 34 routes (34 active, 0 holddown, 0 hidden)
10.10.80.2/32 (1 entry, 1 announced)
*OSPF Preference: 10
Next hop type: Router
Next-hop reference count: 26
Next hop: 10.10.81.10 via xe-0/3/0.0 weight 0x1, selected
Next hop: 10.10.81.23 via ge-1/3/3.0 weight 0xf000 <---------
Huh???
State: <Active Int>
Local AS: 855
Age: 4 Metric: 2
Area: 0.0.0.0
Task: OSPF
Announcement bits (3): 2-LDP 3-KRT 5-Resolve tree 2
AS path: I
inet.3: 7 destinations, 7 routes (7 active, 0 holddown, 0 hidden)
10.10.80.2/32 (1 entry, 1 announced)
State: <FlashAll>
*LDP Preference: 9
Next hop type: Router
Next-hop reference count: 3
Next hop: 10.10.81.10 via xe-0/3/0.0 weight 0x1, selected
Label operation: Push 299776
Next hop: 10.10.81.23 via ge-1/3/3.0 weight 0xf000 <---------
Huh???
Label operation: Push 299856
State: <Active Int>
Local AS: 855
Age: 4 Metric: 1
Task: LDP
Announcement bits (2): 2-Resolve tree 1 3-Resolve tree 2
AS path: I
{master}
se36...@pe1-stjhlab-re0> show ldp route logical-system PE10 10.10.80.2
extensive
Destination Next-hop intf/lsp Next-hop address
10.10.80.2/32 xe-0/3/0.0 10.10.81.10
Session ID 10.10.80.10:0--10.10.80.1:0
ge-1/3/3.0 10.10.81.23
Session ID 10.10.80.10:0--10.10.80.14:0
Bound to outgoing label 299840, Topology entry: 0x8e69980
Ingress route status: Active, Last modified: 00:00:09 ago
{master}
se36...@pe1-stjhlab-re0> traceroute 10.10.80.2 logical-system PE10 no-resolve
traceroute to 10.10.80.2 (10.10.80.2), 30 hops max, 40 byte packets
1 10.10.81.10 0.407 ms 0.282 ms 0.283 ms
2 10.10.80.2 0.904 ms 1.086 ms 1.066 ms
{master}
se36...@pe1-stjhlab-re0> traceroute mpls ldp 10.10.80.2 logical-system PE10
no-resolve
Probe options: ttl 64, retries 3, wait 10, paths 16, exp 7, fanout 16
ttl Label Protocol Address Previous Hop Probe Status
1 299776 LDP 10.10.81.10 (null) Success
2 3 LDP 10.10.81.1 10.10.81.10 Egress
Path 1 via xe-0/3/0.0 destination 127.0.0.64
ttl Label Protocol Address Previous Hop Probe Status
1 299856 LDP 10.10.81.23 (null) Success
2 3 LDP 10.10.81.20 10.10.81.23 Egress
Path 2 via ge-1/3/3.0 destination 127.0.1.64 <--- Why does this get used??
-----------------------
The path via ge-1/3/3 is a backup path chosen by OSPF LFA. As expected IP
packets don't use it when I do a traceroute. The "traceroute mpls ldp" however
seems to use both paths?!? Does this mean that the ingress PE could dump
traffic on both LSPs? I don't want this as only 1 of the 2 is the preferred
path...
Any ideas?
Thanks,
Serge
__________________________________________________________________
Be smarter than spam. See how smart SpamGuard is at giving junk email the boot
with the All-new Yahoo! Mail. Click on Options in Mail and switch to New Mail
today or register for free at http://mail.yahoo.ca
_______________________________________________
juniper-nsp mailing list [email protected]
https://puck.nether.net/mailman/listinfo/juniper-nsp
