describes the system's support for NEMO and explains how it is configured. The
product administration guides provide examples and procedures for configuration
of basic services on the system. It is recommended that you select the
configuration example that best meets your service model and configure the
required elements for that model, as described in the
Cisco ASR 5x00
Packet Data Network Gateway Administration Guide, before using the
procedures in this chapter.
When enabled through
a feature license key, the system includes NEMO support for a Mobile IPv4
Network Mobility (NEMO-HA) on the P-GW platform to terminate Mobile IPv4 based
NEMO connections from Mobile Routers (MRs) that attach to an Enterprise PDN.
The NEMO functionality allows bi-directional communication that is
application-agnostic between users behind the MR and users or resources on
Fixed Network sites.
The same NEMO4G-HA
service and its bound Loopback IP address supports NEMO connections whose
underlying PDN connection comes through GTP S5 (4G access) or PMIPv6 S2a (eHRPD
The following figure
shows a high-level view of LTE NEMOv4 Architecture.
The following use
cases are supported by NEMO in LTE:
Applications, like branch offices, with a mobile router that does not require
Nomadic - Applications
that use a mobile router that does not move while in service, but that may be
moved to a different location and brought back on service (e.g. a kiosk showing
up in a mall one day and in a different location the next day or month).
Moveable - Applications
that need to maintain Dynamic Mobile Network Routing (DMNR) service operational
while moving and crossing PDSN boundaries, such as public safety vehicles.
Service continuity is handled by the mobility protocols (Mobile IP in 3G and
GTP in LTE).
The system supports
the usage of dynamically learned, overlapping customer prefixes. These prefixes
are advertised via BGP.
The following figure
shows a high-level view of the NEMO control plane.
Figure 2. NEMO Control Plane
NEMO includes the
The Cisco NEMO
MR is expected to use the Collocated-Care-of-Address mode to establish a NEMO
MIPv4 session with NEMO4G-HA and as one of the IP endpoints of the NEMO GRE
Tunnel for the transport of user traffic.
supports a potential "dummy" MR-HADDR address that would be configured in every
MR within the same Enterprise or across all served Enterprises (same IP
advertisement of WAN-IP Pools and learned LAN prefixes
eBGP is used to
advertise the Enterprise WAN-IP Pools and the LAN prefixes learned via NEMO for
the associated Enterprise.
supports local authentication for the NEMO MIPv4 RRQ based on preconfigured
N-MHAE-SPI/KEY values on a per Enterprise basis (one unique set for all MRs
belonging to the same Enterprise) or on a global basis (one unique set for all
accepts a minimum of zero LAN prefixes and a maximum of eight prefixes per
mobile router. Anything beyond eight prefixes shall be silently discarded.
supports any prefix length (including /32).
supports dynamic prefix updates.
NEMO4G-HA removes from the associated Enterprise VRF routing
table any prefixes that are not included in a scheduled or ad-hoc NEMO MIPv4
re-registration request from a given MR (assuming these were present in a
previous NEMO MIPv4 RRQ). E-PGW shall update the external VRF router of the
removal of such prefixes on the next eBGP update.
NEMO4G-HA accepts and installs any new prefixes that are
included in a scheduled or ad-hoc NEMO MIPv4 re-registration request to the
associated Enterprise VRF routing table, as long as it doesn't exceed the
maximum number of supported prefixes per MR (up to eight). E-PGW shall update
the external VRF router of the newly installed prefixes on the next eBGP
update. NEMO4G-HA shall accept NEMO MIPv4 RRQs that do not include any prefixes
in the first initial RRQ and it shall accept prefixes advertised in subsequent
of a prefix whose IP address or mask is changed on the MR, the MR will remove
the old IP address/mask and add the new IP address/mask prefix in a scheduled
or ad-hoc NEMO MIPv4 re-registration request and NEMO4G-HA shall remove the old
route and add the new route corresponding to the new prefix to the Enterprise
VRF routing table
supports private and overlapping IP addressing across multiple Enterprises for
the WAN IP pools, MR-HADDR, and LAN prefixes.
a NEMO MIPv4 session only if a NEMO permission has been assigned to the
underlying PDN connection. NEMO permission should be assigned to the underlying
PDN connection via either local configuration (APN parameter) or based on a
NEMO permission AVP assigned by the 3GPP AAA during the PDN authorization. For
local configuration, a new APN parameter is supported to enable NEMO permission
at the APN/PDN level within the P-GW service.
a Mobile IPv4 NEMO Registration Request (RRQ) received from the MR NEMO client.
the first of three Cisco-specific MIPv4 Extensions of type Normal Vendor/Org
Specific Extension (NVSE) that are included in the MIPv4 NEMO RRQ. The three
Cisco-specific NVSEs are placed after the MIPv4 "Identification" field and
before the mandatory MIPv4 "Mobile-Home-Authentication-Extension." NEMO4G-HA
accepts the LAN prefixes (up to eight) encoded in the first Cisco-specific NVSE
(vendor-type = 9). NEMO4G-HA is not expected to process the other two
Cisco-specific NVSEs with vendor-type = 49, which carry the Internal Interface
ID of the MR's Roaming Interface and the MR's Roaming Interface Bandwidth in
follow RFC 3025 "Mobile IP Vendor/Organization Specific Extensions."
User traffic shall
be encapsulated over a GRE tunnel between the MR NEMO client and NEMO4G-HA. The
IP endpoints of the GRE tunnel shall be the IPv4 assigned to the MR modem
during the Enterprise PDN connection setup and the IPv4 address of the
NEMO4G-HA service on the E-PGW.
remove the GRE encapsulation before it forwards the outbound traffic towards
the Enterprise VPN via the associated SGi VLAN interface. Inbound traffic
received through the same SGi VLAN interface shall be encapsulated into a GRE
tunnel before it's passed to the E-PGW service for forwarding to the MR through
the proper GTP/PMIP tunnel.
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
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.
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.
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.
NEMO4G-HA uses the
registration lifetime value locally configured, even though MR's may use the
maximum possible value (65534).
process ad-hoc NEMO RRQ messages.
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.
E-PGW forces IP
packet fragmentation even for IP packets with the DF-bit set.
The LTE NEMO
solution supports intra-chassis Session Redundancy (SR) and Inter-Chassis
Session Redundancy (ICSR) functionalities.
LTE NEMO Call
The following figure
describes the call flow of the NEMOv4 solution.
Figure 3. NEMOv4 Call Flow
The Cisco MR
eHWIC establishes first a connection to the IMS PDN to register to the LTE
Network. The eHWIC's User Id must be properly provisioned on the HSS/SPR to be
After the Cisco
MR eHWIC registers with the LTE network and establishes a connection to the IMS
PDN, then it connects to the appropriate Enterprise PDN based on the locally
configured Enterprise APN.
PDN authorization procedure using S6b, the 3GPP AAA assigns a NEMO permission
via AVP. The AVP is also be available as an APN parameter on the E-PGW to allow
NEMO service at the PDN/Enterprise level.
assigns the MR eHWIC an IPv4 address from the Enterprise IPv4 pool assigned
during PDN authentication.
creates the proper flows internally to forward packets to the corresponding VRF
external to the E-PGW platform using the IPv4 pool configuration on the egress
The MR eHWIC
passed on the assigned IPv4 address to the NEMO application (also called
The MR NEMO
application initiates a Mobile IPv4 registration request (RRQ) using the
following local configuration and the IPv4 address assigned to the eHWIC during
the Enterprise PDN attach procedure (referred to as WAN-IP). The NEMO MIPv4 RRQ
will be carried as a regular user packet over the mobility connection, either
GTP in LTE and PPP/PMIPv6 in eHRPD. The NEMO MIPv4 RRQ includes the following
CCOA - IPv4
address assigned to the eHWIC modem during the Enterprise PDN connection setup
(WAN-IP). The MR NEMO application will use the CCOA/WAN-IP address as the
source of all NEMO packets sent to NEMO4G-HA (control and tunneled user
Mandatory IPv4 address preconfigured in the MR NEMO application. MR-HADDR is
normally used as the source of all NEMO control packets sent to the NEMO4G-HA.
However, the MR NEMO application will use the CCOA as the source for all NEMO
packets (control and tunneled user traffic). Therefore, NEMO4G-HA will ignore
the preconfigured MR-HADDR included in the RRQ, but it will still include it in
the NEMO MIPv4 RRP.
Address - Preconfigured IPv4 address that the MR NEMO application uses as the
destination for all NEMO control and GRE tunneled user data (NEMO4G-HA's IPv4
Prefixes - Locally attached IPv4 networks preconfigured on the MR NEMO
application. LAN prefixes will be encoded in the same Cisco NVSE extension
currently used in the NEMO solution for 3G. The Cisco NVSE included in the
NEMOv4 MIP RRQ is in the form of a TLV.
Mandatory NEMO MN-HA Authentication Extension that includes the SPI and the
authenticator computed using a pre-shared Key. Both SPI and Key are
preconfigured in the MR NEMO application as well.
flags such as, but not limited to, "Reverse Tunnel," "Direct Termination,"
"Tunnel Encapsulation" = GRE.
a MIP registration response (RRP) back to the MR after it performs the
the RRQ using the N-MHAE information included in the RRQ.
the NEMO service based on the NEMO permission attribute assigned to the
associated Enterprise PDN connection.
prefixes advertised in the Cisco NVSE extension included in the NEMO MIPv4 RRQ.
learned prefixes will have to adhere to the current rules of valid pool routes.
The minimum valid mask length is /13 and pool routes can not include 0.0.0.0 or
NEMO4G-HA will accept a minimum of 0 prefixes and a maximum of 8
prefixes. Anything beyond 8 prefixes will be silently discarded.
NEMO4G-HA will also check that the new resultant enterprise
route count (total number of VRF routes) do not exceed the route limit
potentially configured for the given enterprise. If the preconfigured route
limit is exceeded, then NEMO4G-HA will reject the NEMO MIP RRQ. Otherwise,
NEMO4G-HA will install the accepted prefixes in the internal VRF associated
with the Enterprise PDN.
would then propagate the new NEMO routes to the external VRF as part of the
next BGP update.
the NEMO MIP RRP, the MR will install a default route (0.0.0.0/0) in its
routing table to route all traffic through the LTE connection.
packets are encapsulated over GRE using the CCOA/WAN-IP address as the source
and the NEMO4G-HA-Service IPv4 address as the destination of the tunnel.
packets are encapsulated over GRE as well from the NEMO4G-HA to the MR NEMO
application. The source of the GRE tunnel is the NEMO4G-HA-Service IPv4 address
and the destination is the CCOA/WAN-IP address.
Up to 5,000 host
routes spread across multiple VRFs per BGP process. Limited to 6,000 pool
routes per chassis.
Up to 2,048 VRFs
IETF RFC 3025
(February 2001) "Mobile IP Vendor/Organization Specific Extensions"
IETF RFC 1191
(November 1990) "Path MTU Discovery"
Commands used in
the configuration samples in this section provide base functionality to the
extent that the most common or likely commands and/or keyword options are
presented. In many cases, other optional commands and/or keyword options are
available. Refer to the
Interface Reference for complete information regarding all commands.
To configure the
system for NEMO:
Create a VRF on
the router and assign a VRF-ID by applying the example configuration in
neighbors and address family to exchange routing information with a peer router
by applying the example configuration in
Set Neighbors and Address Family.
configuration to flash memory, an external memory device, and/or a network
location using the Exec mode command
configuration. For additional information on how to verify and
save configuration files, refer to the
Administration Guide and the
Line Interface Reference.