This feature is license controlled. Contact your Cisco account
representative for information on how to obtain a license.
When the User Equipment (UE) is unreachable due to 'Power Saving
Mode' or 'Extended Idle Mode DRX', there might be high latency for initial
response before the exchange of packets, which is the time taken by the UE to
establish a connection and initiate data transfer. Owing to high latency, there
is a need to buffer data for a longer duration.
High Latency Communication (HLCOM) feature introduces buffering of MT
data at the S-GW (part of SAEGW), when the UE is in a power saving state and
The HLCOM buffering time duration or the packet count is based on the
first successful DDN Ack carrying those parameters. No new DDNs are initiated
once the call is received and HLCOM parameters start buffering the packets.
Other features such as "Priority Paging" do not override the HLCOM UE. Packets
buffered are not recovered and neither the state of the HLCOM. Buffered packets
are lost on recovery. HLCOM duration and packet count to be buffered is not
recovered. Hence, any packet post recovery triggers DDN.
HLCOM buffers, configurations, and timers are independent of existing
IDLE mode of buffering. This means that the buffer allocated for HLCOM is more
than the IDLE mode memory for buffering data.
The 2-4 KB buffering legacy paging limit is not applicable for HLCOM.
In case of HLCOM devices, upto 4KB data can be buffered per UE in the dedicated
96MB memory. Those devices for which 4k memory is utilized and more is needed,
memory can be extended upto 10k, provided memory available in the extended
memory of size 10MB.
Extended buffering is applied in case buffer duration and suggested
packet count IE in successful DDN Ack is received.
Important: This feature supports only HLCOM buffering for
P-GW, S-GW, and SAEGW calls.
Important: Buffering is done per UE. So irrespective of
the number of bearers or PDNs for a session, all the buffering limits such as
the suggested packet count IE sent in DDNAck and 4KB and 10 KB limits are all
valid for the UE as a whole. HLCOM IE's buffer duration and suggested packet
count in DDNAck are honored only for cause EGTP_CAUSE_REQ_ACCEPTED and
EGTP_CAUSE_UNABLE_TO_PAGE_UE. For other causes, these IE's are ignored.