OPENCONFIG-gNMI - gnmi_get on lldp interface displays incorrect TTL value

[sachin-brm]

Problem Description/Summary :

OPENCONFIG-gNMI - gnmi_get on lldp interface displays incorrect TTL value
Expected Behavior :

gnmi_get on lldp interface should display correct TTL value and it should be in sync with CLICK CLI and CLISH CLI

Topology :

DUT with lldp neighbors

Steps to Repro :

DUT should have lldp neighbors

1. Go to telemetry docker "docker exec -it telemetry bash"
2. Perform gNMI get operation on lldp specific interface and observe the TTL value as "19013".But in CLICK cli TTL value for that interface is "120"

root@sonic:/# gnmi_get -insecure -xpath /openconfig-lldp:lldp/interfaces/interfacce[name=Ethernet0] -target_addr 127.0.0.1:8080
== getRequest:
prefix: <

path: <
elem: <
name: "openconfig-lldp:lldp"

elem: <
name: "interfaces"

elem: <
name: "interface"
key: <
key: "name"
value: "Ethernet0"

encoding: JSON_IETF

== getResponse:
notification: <
timestamp: 1568200012627073033
prefix: <

update: <
path: <
elem: <
name: "openconfig-lldp:lldp"

elem: <
name: "interfaces"

elem: <
name: "interface"
key: <
key: "name"
value: "Ethernet0"

val: <
json_ietf_val: "{"openconfig-lldp:interface":[{"name":"Ethernet0","neighbors":{"neighbor":[{"capabilities":{"capability":[{"name":"openconfig-lldp-types:MAC_BRIDGE","state":{"enabled":true,"name":"openconfig-lldp-types:MAC_BRIDGE"}},{"name":"openconfig-lldp-types:ROUTER","state":{"enabled":true,"name":"openconfig-lldp-types:ROUTER"}}]},"id":"Ethernet0","state":{"chassis-id":"b8:6a:97:fd:c8:c6","chassis-id-type":"MAC_ADDRESS","id":"1","management-address":"10.59.142.211,2001::1","port-description":"Ethernet0","port-id":"twentyfiveGigE1:1","port-id-type":"LOCAL","system-description":"Debian GNU/Linux 9 (stretch) Linux 4.9.0-9-2-amd64 #1 SMP Debian 4.9.168-1+deb9u3 (2015-12-19) x86_64","system-name":"sonic","ttl":19013}}]}}]}"

root@sonic:/#

CLICK CLI output:
root@sonic:/home/admin# show lldp neighbors

LLDP neighbors:

Interface: Ethernet0, via: LLDP, RID: 1, Time: 0 day, 05:30:43
Chassis:
ChassisID: mac b8:6a:97:fd:c8:c6
SysName: sonic
SysDescr: Debian GNU/Linux 9 (stretch) Linux 4.9.0-9-2-amd64 #1 SMP Debian 4.9.168-1+deb9u3 (2015-12-19) x86_64
TTL: 120
MgmtIP: 10.59.142.211
MgmtIP: 2001::1
Capability: Bridge, on
Capability: Router, on
Capability: Wlan, off
Capability: Station, off
Port:
PortID: local twentyfiveGigE1:1
PortDescr: Ethernet0

CLISH CLI OUTPUT:
root@sonic:/home/admin# sonic-cli
sonic#
sonic#
sonic#
sonic# show lldp neighbor

LLDP Neighbors

Interface: Ethernet0,via: LLDP
Chassis:
ChassisID: b8:6a:97:fd:c8:c6
SysName: sonic
SysDescr: Debian GNU/Linux 9 (stretch) Linux 4.9.0-9-2-amd64 #1 SMP Debian 4.9.168-1+deb9u3 (2015-12-19) x86_64
TTL: 19857
Capability: MAC_BRIDGE, ON
Capability: ROUTER, ON
Port
PortID: twentyfiveGigE1:1
PortDescr: Ethernet0

Reproducibility ( Ex:- 3 out of 3 attempts ) Please also update "Reproducible" field :

3

[GarrickHe]

@sachin-brm I'll take a look at this.

[GarrickHe]

@sachin-brm @jeff-yin - The TTL info should actually be removed from the mgmt-framework CLI and GNMI response. SONiC's AppDB doesn't save LLDP TTL for it's neighbors. What's getting displayed for TTL here is actually the time of the remote system.

admin@sonic:~$ redis-cli
127.0.0.1:6379> HGETALL "LLDP_ENTRY_TABLE:Ethernet0"
 1) "lldp_rem_chassis_id_subtype"
 2) "4"
 3) "lldp_rem_sys_name"
 4) "OS10"
 5) "lldp_rem_index"
 6) "2"
 7) "lldp_rem_port_desc"
 8) "ethernet1/1/1:1"
 9) "lldp_rem_sys_cap_supported"
10) "68 00"
11) "lldp_rem_sys_desc"
12) "Dell EMC Networking OS10 Enterprise.\r\nCopyright (c) 1999-2019 by Dell Inc. All Rights Reserved.\r\nSystem Description: OS10 Enterprise.\r\nOS Version: 10.4.9999EX.\r\nSystem Type: Z9100-ON"
13) "lldp_rem_port_id_subtype"
14) "5"
15) "lldp_rem_sys_cap_enabled"
16) "68 00"
17) "lldp_rem_chassis_id"
18) "34:17:eb:2c:d7:00"
19) "lldp_rem_port_id"
20) "ethernet1/1/1:1"
21) "lldp_rem_man_addr"
22) ""
23) "lldp_rem_time_mark"
24) "178432"    <<==== this information is getting displayed
127.0.0.1:6379>

if you look in the output, this is all information for a particular LLDP neighbor saved in appDB. We don't have TTL.

The show lldp neighbor output above is actually getting information from the Linux kernel, not SONiC's appDB.

[GarrickHe]

I filed a bug with SONiC to have them add TTL information to appDB:

sonic-net/sonic-dbsyncd#26

In the meantime, we can remove the TTL field from the output until the issue gets fixed.

[GarrickHe]

Filed pull-request to remove TTL field from output:

#117

Will update the code again when Azure SONiC adds the request TTL information back into appDB.