Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Community Member

Understanding the output of show mpls forwarding-table a.b.c.d detail ...

Hi,there:

I don't understand the meaning of the number 0001400000012000 below, can anybody help me out? more details.

Thanks,

---

lactometer#show mpls forwarding-table 10.200.254.4 detail

Local Outgoing Prefix Bytes tag Outgoing Next Hop

tag tag or VC or Tunnel Id switched interface

20 18 10.200.254.4/32 0 Tu1 point2point

MAC/Encaps=14/22, MRU=1504, Tag Stack{20 18}, via Et0/0/0

00604700881D00024A4008008847 0001400000012000

No output feature configured

---

1 ACCEPTED SOLUTION

Accepted Solutions
Cisco Employee

Re: Understanding the output of show mpls forwarding-table a.b.c

Hi,

your label stack is {20 18} and a label is 4 Bytes with

20 Bits label,

3 cos bits

1 Bottom of stack bit

8 TTL bits.

So 0001400000012000 can be read as 00014000 00012000.

Hex 0x00014000 = binary 00000000000000010100 000 0 00000000 = label 20 cos 0 S 0 TTL 0

Hex 0x00012000 = binary 00000000000000010010 000 0 00000000 = label 18 cos 0 S 0 TTL 0

Be aware that exp/cos bits, s and TTL are set when getting the IP packet and thus will not be 0 on outgoing labeled packets. The 0 is just a placeholder.

Hope this helps! Please use the rating system.

Regards, Martin

1 REPLY
Cisco Employee

Re: Understanding the output of show mpls forwarding-table a.b.c

Hi,

your label stack is {20 18} and a label is 4 Bytes with

20 Bits label,

3 cos bits

1 Bottom of stack bit

8 TTL bits.

So 0001400000012000 can be read as 00014000 00012000.

Hex 0x00014000 = binary 00000000000000010100 000 0 00000000 = label 20 cos 0 S 0 TTL 0

Hex 0x00012000 = binary 00000000000000010010 000 0 00000000 = label 18 cos 0 S 0 TTL 0

Be aware that exp/cos bits, s and TTL are set when getting the IP packet and thus will not be 0 on outgoing labeled packets. The 0 is just a placeholder.

Hope this helps! Please use the rating system.

Regards, Martin

2568
Views
5
Helpful
1
Replies
CreatePlease to create content