Network Mobility (NEMO)
NEMO Overview ▀
Cisco ASR 5x00 Packet Data Network Gateway Administration Guide ▄
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Session Interactions
The following session interaction scenarios are supported between NEMO and the underlying PDN connection made
over eHRPD or LTE access.
In the following circumstances, NEMO4G-HA shall withdraw the associated prefix routes from the Enterprise VRF
routing table, update the eBGP neighbors and free up all internal resources allocated for the underlying PDN connection
and NEMO session:
When the eHRPD terminates the underlying PDN connection (PPP-VSNCP-Term-Req sent to MR and PMIP-
BU with lifetime = 0 sent to E-PGW).
When the MR terminates the PPP/PDN connection when accessing the network via eHRPD.
After an eUTRAN (LTE) detach procedure initiated by the MR or MME.
NEMO4G-HA shall not be able to process any NEMO MIPv4 RRQs if there's no underlying PDN connection
associated to those RRQs (PMIPv6 or GTP). In other words, NEMO MIPv4 RRQs can be accepted and processed only
if an Enterprise PDN connection has been established with E-PGW by the mobile router.
NEMO4G-HA shall silently ignore NEMO MIPv4 RRQs if the underlying PDN connection associated to each of those
RRQs does not have the NEMO permission indication. This applies to both eHRPD and LTE access.
NEMO4G-HA shall forward (not drop) user data using MIP or GRE tunneling (UDP/434 or IP Protocol/47,
respectively) to the external enterprise VRF if such data is not destined to the NEMO4G-HA IP address. This applies to
PDN connections that have or do not have the NEMO Permission indication. This shall also apply to both eHRPD and
LTE access.
Any failure on either the authentication or authorize of a NEMO MIPv4 session shall not affect the underlying PDN
connection established between the mobile router and the E-PGW via eHRPD or LTE. For example, if the security
credentials do not match between the MR NEMO client and NEMO4G-HA, NEMO4G-HA can reject the NEMO
MIPv4 RRQ, but the associated PDN connection shall not be terminated.
NEMO Session Timers
NEMO4G-HA uses the registration lifetime value locally configured, even though MR's may use the maximum possible
value (65534).
NEMO4G-HA can process ad-hoc NEMO RRQ messages.
Enterprise-wide Route Limit Control
NEMO4G-HA supports a control mechanism to limit the maximum number of prefixes/routes that a given enterprise
can register, including the pools for WAN IP assignments.
When the maximum number of routes is reached, a syslog message is generated. Once the number of routes goes under
the limit, a syslog message is generated for notification.
Forced Fragmentation
E-PGW forces IP packet fragmentation even for IP packets with the DF-bit set.
Redundancy/Reliability
The LTE NEMO solution supports intra-chassis Session Redundancy (SR) and Inter-Chassis Session Redundancy
(ICSR) functionalities.
