diff --git a/library/GSM_RestOctets.ttcn b/library/GSM_RestOctets.ttcn
index 94dce04..2be96a4 100644
--- a/library/GSM_RestOctets.ttcn
+++ b/library/GSM_RestOctets.ttcn
@@ -16,6 +16,270 @@
 import from General_Types all;
 import from Osmocom_Types all;
 import from RLCMAC_CSN1_Types all;
+import from GSM_Types all;
+
+/* 10.5.2.16 IA (Immediate Assignment) Rest Octets */
+type record IaRestOctets {
+	BIT2		presence,
+	IaRestOctLL	ll optional,
+	IaRestOctLH	lh optional,
+	IaRestOctHL	hl optional,
+	IaRestOctHH	hh optional
+} with {
+	variant (presence) "CSN.1 L/H"
+	variant (ll) "PRESENCE(presence = '00'B)"
+	variant (lh) "PRESENCE(presence = '01'B)"
+	variant (hl) "PRESENCE(presence = '10'B)"
+	variant (hh) "PRESENCE(presence = '11'B)"
+
+	/* The TITAN's RAW encoder generates an octet-aligned octetstring,
+	 * so we should make sure that unused bits contain proper padding. */
+	variant "PADDING(yes), PADDING_PATTERN('00101011'B)"
+};
+
+type record IaRestOctLL {
+	BIT1		compressed_irat_ho_info_ind
+} with {
+	variant (compressed_irat_ho_info_ind) "CSN.1 L/H"
+};
+
+type record IaRestOctLH {
+	BIT2		presence,
+	EgprsUlAss	egprs_ul optional,
+	octetstring	multiblock_dl_ass optional /* TODO */
+} with {
+	variant (egprs_ul) "PRESENCE(presence = '00'B)"
+	variant (multiblock_dl_ass) "PRESENCE(presence = '01'B)"
+};
+
+/* EGPRS Packet Uplink Assignment */
+type record EgprsUlAss {
+	BIT5 ext_ra,
+	BIT1 ats_present,
+	AccessTechnologiesRequestRepetition ats optional,
+	BIT1			presence,
+	EgprsUlAssignDyn	dynamic optional,
+	EgprsUlAssignMultiblock	multiblock optional
+} with {
+	variant (ats)	"PRESENCE(ats_present = '1'B)"
+	variant (dynamic)	"PRESENCE(presence = '1'B)"
+	variant (multiblock)	"PRESENCE(presence = '0'B)"
+	/* See https://bugs.eclipse.org/bugs/show_bug.cgi?id=562488 */
+	variant (ext_ra) "BYTEORDER(last)" // FIXME: should be first
+};
+
+type record EgprsUlAssignDyn {
+	uint5_t		tfi_assignment,
+	BIT1		polling,
+	BIT1		spare ('0'B),
+	uint3_t		usf,
+	BIT1		usf_granularity,
+	BIT1		p0_present,
+	uint4_t		p0 optional,
+	BIT1		pr_mode optional,
+	EgprsChCodingCommand	egprs_ch_coding_cmd,
+	BIT1		tlli_block_chan_coding,
+	BIT1		bep_period2_present,
+	BIT4		bep_period2 optional,
+	BIT1		resegment,
+	EgprsWindowSize	egprs_window_size,
+	BIT1		alpha_present,
+	uint4_t		alpha optional,
+	uint5_t		gamma,
+	BIT1		ta_index_present,
+	uint4_t		ta_index optional,
+	BIT1		tbf_starting_time_present,
+	TbfStartingTime	tbf_starting_time optional
+	/* TODO: Additions for Rel-7 */
+} with {
+	variant (p0)		"PRESENCE(p0_present = '1'B)"
+	variant (pr_mode)	"PRESENCE(p0_present = '1'B)"
+	variant (bep_period2)	"PRESENCE(bep_period2_present = '1'B)"
+	variant (alpha)		"PRESENCE(alpha_present = '1'B)"
+	variant (ta_index)	"PRESENCE(ta_index_present = '1'B)"
+	variant (tbf_starting_time)	"PRESENCE(tbf_starting_time_present = '1'B)"
+};
+
+type record EgprsUlAssignMultiblock {
+	BIT1		alpha_present,
+	uint4_t		alpha optional,
+	uint5_t		gamma,
+	TbfStartingTime	tbf_starting_time,
+	BIT2		nr_radio_blocks_allocated,
+	BIT1		p0_present,
+	uint4_t		p0 optional,
+	BIT1		spare ('0'B) optional,
+	BIT1		pr_mode optional
+	/* TDO: Additions for Rel-6 */
+} with {
+	variant (alpha)		"PRESENCE(alpha_present = '1'B)"
+	variant (p0)		"PRESENCE(p0_present = '1'B)"
+	variant (spare)		"PRESENCE(p0_present = '1'B)"
+	variant (pr_mode)	"PRESENCE(p0_present = '1'B)"
+};
+
+type record IaRestOctHL {
+	uint6_t		freq_par_len,
+	BIT2		padding ('00'B) optional,
+	uint6_t		maio optional,
+	octetstring	mobile_allocation optional
+} with {
+	variant (freq_par_len)	"LENGTHTO(mobile_allocation,maio,padding)"
+/*
+	variant (padding)	"PRESENCE(freq_par_len != 0)"
+	variant (maio)		"PRESENCE(freq_par_len != 0)"
+	variant (mobile_allocation) "PRESENCE(freq_par_len != 0)"
+*/
+};
+
+type record IaRestOctHH {
+	/* Packet Assignment discriminator:
+	 * Packet Uplink / Downlink Assignment (0)
+	 * Second Part Packet Assignment (1) */
+	BIT1			pa_disc,
+	PacketAssignUnion	pa
+} with {
+	variant (pa) "CROSSTAG(spa, pa_disc = '1'B; uldl, pa_disc = '0'B)"
+};
+
+type union PacketAssignUnion {
+	SecondPartAssign	spa,
+	PacketUlDlAssign	uldl
+};
+
+type record SecondPartAssign {
+	BIT1		r99, /* L / H */
+	BIT1		presence optional,
+	BIT5		ext_ra optional
+} with {
+	variant (r99) "CSN.1 L/H"
+	variant (presence) "PRESENCE(r99 = '1'B)" /* H */
+	variant (ext_ra) "PRESENCE(presence = '1'B)"
+	/* See https://bugs.eclipse.org/bugs/show_bug.cgi?id=562488 */
+	variant (ext_ra) "BYTEORDER(last)" // FIXME: should be first
+};
+
+type record PacketUlDlAssign {
+	BIT1			ass_disc,
+	PacketUlDlAssignUnion	ass
+} with {
+	variant (ass) "CROSSTAG(dl, ass_disc = '1'B; ul, ass_disc = '0'B)"
+};
+
+type union PacketUlDlAssignUnion {
+	PacketUlAssign		ul,
+	PacketDlAssign		dl
+};
+
+type record PacketUlAssign {
+	BIT1			presence,
+	PacketUlAssignDyn	dynamic optional,
+	PacketUlAssignSgl	single optional
+	/* TODO: Estended RA, PFI */
+} with {
+	variant (dynamic)	"PRESENCE(presence = '1'B)"
+	variant (single)	"PRESENCE(presence = '0'B)"
+};
+
+type record PacketUlAssignDyn {
+	uint5_t		tfi_assignment,
+	BIT1		polling,
+	BIT1		spare ('0'B),
+	uint3_t		usf,
+	BIT1		usf_granularity,
+	BIT1		p0_present,
+	uint4_t		p0 optional,
+	BIT1		pr_mode optional,
+	ChCodingCommand	ch_coding_cmd,
+	BIT1		tlli_block_chan_coding,
+	BIT1		alpha_present,
+	uint4_t		alpha optional,
+	uint5_t		gamma,
+	BIT1		ta_index_present,
+	uint4_t		ta_index optional,
+	BIT1		tbf_starting_time_present,
+	TbfStartingTime	tbf_starting_time optional
+} with {
+	variant (p0)		"PRESENCE(p0_present = '1'B)"
+	variant (pr_mode)	"PRESENCE(p0_present = '1'B)"
+	variant (alpha)		"PRESENCE(alpha_present = '1'B)"
+	variant (ta_index)	"PRESENCE(ta_index_present = '1'B)"
+	variant (tbf_starting_time)	"PRESENCE(tbf_starting_time_present = '1'B)"
+};
+
+type record PacketUlAssignSgl {
+	BIT1		alpha_present,
+	uint4_t		alpha optional,
+	uint5_t		gamma,
+	BIT2		padding ('01'B),
+	TbfStartingTime	tbf_starting_time
+	/* TODO: P0 / PR_MODE */
+} with {
+	variant (alpha)		"PRESENCE(alpha_present = '1'B)"
+};
+
+type record PacketDlAssign {
+	GprsTlli	tlli,
+	BIT1		group1_present,
+	PacketDlAssG1	group1 optional,
+	BIT1		ta_index_present,
+	uint4_t		ta_index optional,
+	BIT1		tbf_starting_time_present,
+	TbfStartingTime	tbf_starting_time optional,
+	BIT1		p0_present,
+	uint4_t		p0 optional,
+	BIT1		pr_mode optional
+	/* TODO: EGPRS window size, etc. */
+} with {
+	variant (group1)	"PRESENCE(group1_present = '1'B)"
+	variant (ta_index)	"PRESENCE(ta_index_present = '1'B)"
+	variant (tbf_starting_time)	"PRESENCE(tbf_starting_time_present = '1'B)"
+	variant (p0)		"PRESENCE(p0_present = '1'B)"
+	variant (pr_mode)	"PRESENCE(p0_present = '1'B)"
+};
+
+type record PacketDlAssG1 {
+	uint5_t		tfi_assignment,
+	BIT1		rlc_mode,
+	BIT1		alpha_present,
+	uint4_t		alpha optional,
+	uint5_t		gamma,
+	BIT1		polling,
+	BIT1		ta_valid
+} with { variant "" };
+
+type record TbfStartingTime {
+	uint5_t		t1,
+	uint6_t		t3,
+	uint5_t		t2
+};
+
+/* 10.5.2.17 IAR (Immediate Assignment Reject) Rest Octets */
+type record IARRestOctets {
+	ExtRAList		ext_ra_list,
+	BIT1			rel13_ind, // L/H
+	uint3_t			rcc optional
+	/* Addition in Rel-15: PEO IMM Cell Group Details struct */
+} with {
+	variant (rel13_ind) "CSN.1 L/H"
+	variant (rcc) "PRESENCE(rel13_ind = '1'B)"
+
+	/* The TITAN's RAW encoder generates an octet-aligned octetstring,
+	 * so we should make sure that unused bits contain proper padding. */
+	variant "PADDING(yes), PADDING_PATTERN('00101011'B)"
+};
+
+/* Optional extended RA: 0 | 1 < Extended RA 1 : bit (5) > */
+type record length(4) of ExtRAOpt ExtRAList;
+type record ExtRAOpt {
+	BIT1			presence, // L/H
+	BIT5			ext_ra optional
+} with {
+	variant (presence) "CSN.1 L/H"
+	variant (ext_ra) "PRESENCE(presence = '1'B)"
+	/* See https://bugs.eclipse.org/bugs/show_bug.cgi?id=562488 */
+	variant (ext_ra) "BYTEORDER(last)"
+};
 
 /* 10.5.2.33b SI 2quater Rest Octets */
 type record SI2quaterRestOctets {